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Quinine Facts, Benefits, and Dangers for Malaria and Leg Cramps

Linda Crampton has an honors degree in biology. She is interested in chemicals from other organisms and their benefits to the human body.

Anopheles stephensi feeding on human blood; this species transmits malaria

Anopheles stephensi feeding on human blood; this species transmits malaria

What Is Quinine?

Quinine is a bitter chemical present in the bark of cinchona trees, which are native to South America. Multiple species of the genus Cinchona produce the chemical. It's an interesting substance that is used as a medicine to treat malaria. It's also used in much lower doses to provide the bitter taste of tonic water.

Some people take quinine to help their nighttime leg cramps, but health agencies say that it's not advisable to use it for this purpose. The chemical can cause a range of side effects, some of which may be dangerous. The only recommended use of the substance at the moment is as an antimalarial medication.

An Important Note

The information in this article is intended for general interest. Anyone who has questions or concerns about quinine, malaria treatment, or nighttime leg cramp treatment should consult a doctor.

Facts About Cinchona Trees

Cinchona plants are evergreen and grow as small trees or as shrubs. The trees reach a height of around fifteen meters. Their leaves range from oval in shape to lanceolate (shaped like a lance). The plants produce clusters of tubular white or pink flowers. Cinchona officinalis is the national tree of Peru. The country contains many other species in the genus.

The bark of the trees is sometimes known as Jesuits' bark or powder. The Jesuits introduced the plant to Europe from South America. Until the 1940s, quinine from the bark of a cinchona tree was the best treatment for malaria. The purified medication is still used to treat the disease, but other drugs are often preferred when they are available. The intact bark of the cinchona tree contains other biologically active chemicals in addition to quinine. Scientists are exploring these chemicals.

Tonic water contains quinine. When ultraviolet light is shone on quinine, it fluoresces, releasing a blue light.

Tonic water contains quinine. When ultraviolet light is shone on quinine, it fluoresces, releasing a blue light.

Characteristics of Quinine

Quinine is a natural chemical but can also be made synthetically. It's classified as an alkaloid. Alkaloids have a ring containing at least one nitrogen atom in their structure. They often have noticeable effects on the human body. Examples of alkaloids that have significant effects on humans include nicotine, caffeine, and morphine. The name of an alkaloid often ends in "ine".

If a glass of tonic water is exposed to sunlight, it emits a faint blue glow. The action of the ultraviolet rays in sunlight on the quinine in the tonic water is responsible for this glow. Quinine is fluorescent. A fluorescent substance emits light of one color when it's exposed to light of another color (or to another form of electromagnetic radiation). If tonic water is exposed to a stronger UV light source than sunlight, it will emit a brighter glow.

The Life Cycle of the Malaria Parasite

Malaria is caused by a one-celled parasitic organism called Plasmodium. Multiple species in the genus can cause the disease. Each species has multiple stages in its life cycle, which are described below.

Stages in the Human Body

Malaria parasites in the sporozoite stage enter a person’s blood in the saliva of an infected Anopheles mosquito when the insect bites its victim. The bite delivers saliva containing an anticoagulant. The anticoagulant stops blood from clotting and allows the mosquito to withdraw liquid blood.

Once the sporozoites have entered the body of their host, they invade the liver cells. Here they reproduce, producing merozoites. The merozoites enter red blood cells. Inside the blood cells, the parasites continue to multiply. The cells eventually burst open, releasing new parasites, which can then infect more cells. Infected red blood cells all open at about the same time, releasing toxins that cause the victim to experience the typical chills, fever, headache, and muscle pain of malaria.

Stages in the Mosquito's Body

Some merozoites produce gametocytes while they are in the red blood cells. The gametocytes enter the blood and then enter a mosquito's body during a bite. The parasite continues to develop in the mosquito's gut.

  • The gametocytes become male or female gametes inside the mosquito.
  • A male and female gamete join to form an ookinete.
  • The ookinete enters the lining of the mosquito's gut and becomes an oocyst.
  • The oocyst produces new sporozoites.
  • The sporozoites migrate to the mosquito's salivary glands, enabling the life cycle to repeat.

According to the World Health Organization, in 2020 (the latest year with statistics), there were 241 million cases of malaria around the world. 627,000 people are believed to have died from the disease in 2020.

How Does Quinine Help Malaria?

Plasmodium breaks down the hemoglobin in red blood cells for food. Hemoglobin is the red pigment that transports oxygen in the blood. As Plasmodium digests hemoglobin, it releases a toxic substance called heme from the hemoglobin. The parasite converts this toxin into a substance called hemozoin or malarial pigment, which is nontoxic. It’s thought that quinine inhibits one of the parasite’s enzymes, preventing the conversion of heme into malarial pigment. The heme therefore kills the parasite.

As described above, the malaria parasite exists in different forms in different stages of its life cycle. Quinine appears to be active against only one form of the parasite (the merozoite in red blood cells), so malaria symptoms may reappear if treatment with the chemical is stopped. The Government of Canada says that quinine should be administered in combination with another drug.

Possible Side Effects of Quinine Treatment

Quinine treatment for malaria can be very helpful but sometimes results in a condition called cinchonism. Symptoms of mild cinchonism may include:

  • headache
  • nausea
  • vomiting
  • abdominal pain
  • diarrhea
  • sweating
  • confusion
  • dizziness

A person may also experience blurred vision, a rash, tinnitus (ringing in the ears), and the loss of high-frequency hearing. These symptoms often disappear once quinine therapy is stopped. They should be monitored carefully, though.

A stained slide showing the malarial parasite (blue) in blood and the red blood cells

A stained slide showing the malarial parasite (blue) in blood and the red blood cells

Potential Problems and Precautions

There are some additional concerns related to quinine. A doctor should be consulted whenever a person takes the medication.


Quinine stimulates the release of insulin from the pancreas. Insulin is the hormone that triggers blood glucose (or blood sugar) to enter cells. Too much insulin causes hypoglycemia, which is an abnormally low level of glucose in the blood.


Malaria can be dangerous for a pregnant woman and for her fetus, so it must be treated. If a pregnant woman is given quinine as a treatment, the dose and the woman's response to the medication should be carefully monitored. It's important that the woman tells the doctor that she is pregnant if they don't already know this fact.

The Government of Canada reference shown below says that pregnant women often experience minor hypoglycemia when treated with quinine. A woman should discuss this situation with her doctor, especially if she develops the problem.

Severe Symptoms

Severe cinchonism may produce serious effects such as heart arrhythmia, loss of sight, a decreased number of blood platelets, kidney failure, low blood pressure, and anaphylaxis (a life-threatening and body-wide allergic response). A doctor should be consulted immediately if major symptoms appear. Another potential problem is that quinine can sometimes interfere with the action of other drugs that a person is taking.

Antimalarial Drugs

Malaria is one of the world's major health problems. Many antimalarial drugs are available, including quinine, which may be used on its own or in combination with other medications.

The antimalarial drug or drugs of choice depends on several factors, including the species of Plasmodium involved, the resistance of the parasite to the drug, the mechanism of action of the drug, and the condition of the patient. The development of parasite resistance to a particular medication is a frequent problem.

Doctors have to prescribe the medications that are both widely available and effective in their area. In some parts of the world, they may be limited in their choice. Artemisinin in combination with another drug is often considered to be the best treatment for malaria today, but there are signs that the parasite is developing resistance to this combination. Multiple drugs for malaria are needed at the moment so that doctors can choose the best medicine or the best combination of medicines for their patients.

Like other trees and shrubs in the genus Cinchona, the bark of Cinchona officinalis contains quinine.

Like other trees and shrubs in the genus Cinchona, the bark of Cinchona officinalis contains quinine.

Quinine and Leg Cramps

Quinine has been used to treat the painful leg cramps that some people experience at night. This is an off-label use of the medication, however. An off-label use is one that hasn't been approved by a regulatory agency (such as the FDA or Food and Drug Administration in the United States).

A leg cramp is a sudden and painful contraction of a muscle that lasts from seconds to minutes. The pain is usually in the calf but may develop in the thigh or foot instead. It often appears just before a person falls asleep. The cramps may occur on their own or may be accompanied by arthritis or restless legs syndrome. The likelihood of experiencing leg cramps increases as we age.

Quinine may reduce the excitability of the nerves that control the leg muscles. The results of clinical trials to test the effects of the chemical on leg cramps have been mixed, however. Some experiments suggest that quinine can help, while others conclude that the chemical has no effect.

Quinine tablets must be obtained by prescription in the United States. The FDA doesn't recommend the use of quinine for leg cramps due to the potential for serious side effects, including heart rhythm abnormalities and thrombocytopenia (a low platelet level). The NIH or National Institutes of Health warns people that they shouldn't use the chemical to either treat or prevent the cramps.

Tonic Water Features

A dilute source of quinine can be found in grocery stores, Quinine is added to tonic water in very small quantities to produce the bitter taste that is enjoyed in some alcoholic drinks.

In British colonial times, tonic water had a much higher quinine content than today and was used to treat malarial symptoms. It really was a “tonic” water. Quinine is so bitter that drinking tonic water can cause vomiting unless the solution is very dilute or unless the chemical's taste is masked by sugar and flavorings.

The FDA limits the amount of quinine in tonic water today. A glass of tonic water contains around 20 mg of quinine, which is much less than a normal therapeutic dose. Even so, there are anecdotal reports of people with nighttime leg cramps who have drunk tonic water before going to bed and have been relieved of their cramps. The Harvard Health reference source mentioned below says that drinking a few ounces of tonic water "isn't likely" to prevent cramps, however.

It's important that a person doesn't drink large amounts of tonic water, which might supply a dangerous dose of quinine. If cramps aren't relieved by a normal quantity of tonic water or by the commonly recommended treatments mentioned below, a doctor should be seen.

Drinking water may help nighttime legs cramps, especially if the water contains minerals.

Drinking water may help nighttime legs cramps, especially if the water contains minerals.

Other Possible Treatments for Leg Cramps

Other treatments may help leg cramps. Stretching the legs, massaging the leg muscles, applying cold compresses or hot pads to the cramped area, or taking hot baths may relieve the pain.

Increasing the intake of nutrients such as potassium, calcium, magnesium, and vitamin B complex (within safe limits) may also help leg cramps. Drinking enough fluids may be beneficial, too. Some people report that a sports drink containing a high level of minerals is helpful.

When I wrote the first edition of this article, I had never experienced a nighttime leg cramp. Since then, I've experienced nocturnal cramps in a calf muscle and in a foot. They are definitely painful events! I haven't suffered from any more cramps since I've started taking a daily mutivitamin/multimineral supplement. I don't know for certain that the cramps have stopped because of the supplement, though.

If you plan on taking a daily vitamin and mineral supplement, you should do some research about the best type to take. A woman's need for iron decreases after menopause, for example. Since excess iron can be dangerous, a supplement designed for a younger woman may not be suitable for a postmenopausal one.

Should You Take Quinine?

Doctors can still prescribe quinine, but the FDA has only approved its use for the treatment of malaria. In all other cases, it believes that the risks outweigh any possible benefits. If your doctor suggests that you take the medication, you should ask for detailed information about the benefits and dangers of taking the drug for your health problem.

If you're considering regularly drinking tonic water to get a low dose of quinine you should also seek your doctor’s advice, especially if you're pregnant. In addition, you should check how much quinine your chosen brand of tonic water contains. Drinking a large quantity of the water could be dangerous. Cinchona bark and quinine are interesting substances and can be very useful, but they need to be treated with care.


This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

Questions & Answers

Question: Is a 2-liter bottle of sugar-free tonic water too much to drink in a day in order to relieve arthritis pain and muscle pain in a 67-year-old woman? The tonic water has been helping immensely.

Answer: As I say in the article, it’s important to know much quinine is in your favourite tonic water so that you can work out the daily dose that you’re receiving. You should contact the manufacturer to discover this information. Going to the company’s website and then emailing them might be a good way to do this. Once you know the amount of quinine in two litres of the tonic water, you should check with your doctor to find out how safe that amount is and how it may affect your general health and any other medical conditions that you have.

I’m glad the tonic water is so helpful for you, but safety is important. You need to remember that in many places quinine is only recommended for malaria treatment and not as a treatment for any other disorder. It’s important to do some research to discover how much quinine you’re ingesting and to get a medical opinion about whether it’s safe.

© 2010 Linda Crampton


Linda Crampton (author) from British Columbia, Canada on November 16, 2019:

Hi, Luis. Thanks for the comment. Mosquitoes can cause some unpleasant diseases. I hope we're soon able to deal with them better.

Luis G Asuncion from City of San Jose Del Monte, Bulacan, Philippines on November 16, 2019:

Very informational. In my country, there is a mosquito disease also, we call it as dengue. Thanks for sharing.

Linda Crampton (author) from British Columbia, Canada on December 18, 2018:

Hi, Mary. You need to ask your doctor this question. I'm not a physician, so I can't help you.

Mary Erskine on December 18, 2018:

Will I have any side effects coming off quinine after being on them for 18 years

Linda Crampton (author) from British Columbia, Canada on March 01, 2013:

I'm sorry to hear that your sister had to enter the ICU, STy. I hope she recovers very soon. Thank you for sharing your experience.

STy on March 01, 2013:

My Sister in Africa was given Quinine for possible Malaria, she is in an ICU bed as we speak from side effects of taking this drug.

Linda Crampton (author) from British Columbia, Canada on February 03, 2013:

Thanks for the comment and the vote, moonlake. Thank you for sharing your husband's personal experience, too. I hope he finds (or has found) a good replacement for quinine.

moonlake from America on February 03, 2013:

My husband use to use quinine for his legs now he can't get it. It really worked. Great hub voted up.

Linda Crampton (author) from British Columbia, Canada on December 07, 2012:

Thanks for the visit and the comment, pickles. You've raised a very good point. There are different causes for leg cramps!

pickles on December 07, 2012:

Not looking for an 'answer' but I am wondering if perhaps the reason quinine sometimes works for leg cramps and sometimes doesn't, is that there could be different reasons for the leg cramps. Like, over use, or some other parasite, perhaps at this time unknown.

Linda Crampton (author) from British Columbia, Canada on June 16, 2012:

Thank you very much, Marlene. I appreciate your comment!

Marlene on June 16, 2012:

Alicia c just wanted to say you answers everyone's questions so nicely well done. I've been reading other blogs and have been very disappointed in the way some write on then... Thankyou

Linda Crampton (author) from British Columbia, Canada on May 07, 2012:

Hi, Peggy. Quinine can stimulate the pancreas to release insulin, thereby lowering the blood glucose level, but I've never heard of quinine or tonic water causing pancreatitis This would be a good question to ask your husband's doctor!

Peggy on May 07, 2012:

My husband has had 2 bouts with pancreatitis and,altho he was a light drinker, he has sworn off all alcohol. We were just on vacation at an all-inclusive resort for 2 wks and he enjoyed several tonics with lime juice per day. We got home yesterday and he ended up in the hospital today with another case of acute pancreatitis. Could the tonic have caused this?

Linda Crampton (author) from British Columbia, Canada on March 08, 2012:

Thank you for the information, patience. I'm glad that you had no problems while taking quinine. It's important that pregnant women follow their doctor's instructions and advice if they take quinine.

patience on March 08, 2012:

quinine is safe for a pregnant woman, 600mg taken orally every 8hrs is d recommended dose for a pregnant woman in her first trimester by WHO, i have once taken it that way and there was no miscarriage

Linda Crampton (author) from British Columbia, Canada on November 02, 2011:

That's interesting information, Nellie. I've read reports from other people who say that tonic water helps their leg cramps too, although researchers say the results of their surveys are mixed, with quinine helping some people but not others. Medical researchers do say that a doctor should be consulted before tonic water is drunk regularly because there may be serious side effects.

Nellie Hocutt on November 02, 2011:

I keep tonic water in my frig. I sometimes wake up with severe leg cramps and have learned that just drinking a swallow or two will knock it dead in it's tracks. Wonderful stuff.

Linda Crampton (author) from British Columbia, Canada on October 26, 2011:

Fosuwaah, you MUST check with your doctor before taking quinine if you are pregnant. In addition, quinine is medically prescribed only for someone with malaria. If you have malaria your doctor may want to try another medication as well as or instead of quinine.

Fosuwaah on October 26, 2011:

is it good for a pragnant woman to take quinine? am 25 weeks pragnant.

Linda Crampton (author) from British Columbia, Canada on August 31, 2011:

Hi, Benon. According to the following authoritative websites, a high dose of quinine may cause a miscarriage. If pregnant women do take quinine (with a doctor's recommendation) they need to be very careful not to take a quinine overdose.

Benon on August 31, 2011:

Quinine does not cause miscarriages

jay on March 22, 2011:

will do thanx ,its just dat i've managed to get way more info out of you than i did from my doctor..maybe its cause i didn't ask much i was too freaked out from the whole blindness the time i literary couldn't see anything,but i didn't even know some of these side effects..i enjoyed reading it btw..i know more now.thank you

Linda Crampton (author) from British Columbia, Canada on March 22, 2011:

Hi Jay. I’m a high school biology teacher, not a doctor. Please make sure that you CHECK WITH YOUR DOCTOR to see if it’s safe to continue taking quinine. One of the side effects of taking quinine can be blurred vision, as I state in my hub. My research suggests that quinine-induced blindness is rare but has occurred in people taking large doses of quinine. You MUST seek medical advice before you even consider taking quinine again. Good luck.

jay on March 22, 2011:

i live in africa n recently had malaria,in the past id had it but no other drug worked except for quinine..n this tym it caused blindness..after a few cups of juice i cud see blurred of course but my vision got better within a couple of days..i can see dimly now tho i've been told with time n increase of glucose i will regain my sight completely,is there any danger if i contninue to use it?since no other drugs seem to work?

Linda Crampton (author) from British Columbia, Canada on January 09, 2011:

I was glad to read your response, Martie. Best wishes.

Martie Coetser from South Africa on January 08, 2011:

My life is a neverending feast since I left Jo. Leaving him was the best thing I've ever done to myself. Thanks for the interest you've shown. Take good care of yourself!

Linda Crampton (author) from British Columbia, Canada on January 08, 2011:

Martie, I am so very sorry for the experience that you have described. What a heartbreaking situation. I have just read your hubs about your experiences with your ex-husband. I hope so much that life is very much better for you now.

Martie Coetser from South Africa on January 08, 2011:

When my son (second child) was one year old, I fell pregnant because I did not take the Pill for four days – forgot it at home when we went on holiday. Unfortunately I was married to a man who loved only himself. 'No' was a word he refused to accept. When I realised I was pregnant, must have been 6 weeks, I simply took an overdose Quinine. It was an extremely painful and traumatic experience – the miscarriage – and I cried my heart out while I was holding the little fetus in my hand. I still wonder who he/she was and could have been today. Circumstances sometimes force women/men to do things they regret for the rest of their lives. Thank you for this important information about Quinine.

Linda Crampton (author) from British Columbia, Canada on December 30, 2010:

Thank you, Prasetio. I enjoyed creating the hub. I'm glad that you found it useful.

prasetio30 from malang-indonesia on December 30, 2010:

Good information, Alicia. I have admit to you that I never knew about this before. This is a good news for medication world. Personally I am glad to know that quinine is best known as an anti-malarial drug. Although physically quinine shaped is like a mosquito. This time, I learn much from you. Keep on writing and share useful information like this . I look forward to reading more. I give my vote to you. Thank you very much.

Blessing and hugs, Prasetio:)

Linda Crampton (author) from British Columbia, Canada on December 29, 2010:

Thank you, megmccormick!

megmccormick from Utah on December 29, 2010:

I feel so much better about my gin and tonics now!! Gotta keep those leg cramps at bay! Thanks for an informative hub!

Linda Crampton (author) from British Columbia, Canada on November 09, 2010:

Thank you for your comment, GmaGoldie. It was very interesting to hear that you are craving tonic water when you are in pain. I love learning from people’s comments! I hope your shoulder heals soon.

Kelly Kline Burnett from Madison, Wisconsin on November 09, 2010:

Fascinating information. I have been craving Tonic Water with quinine. I didn't know what quinine was. I am fighting a frozen shoulder and the anti-inflammatory drugs really help the pain. Normally pain killers and I are not friends but the frozen shoulder is very very painful.

This is important information as I sip my Tonic Water with ice with quinine - thank you very much!

Linda Crampton (author) from British Columbia, Canada on October 08, 2010:

Thanks for an interesting comment, Nell. I’ve never taken quinine myself, so it’s good to hear about people’s personal experiences with it.

Nell Rose from England on October 08, 2010:

Hi, we had to take it when we went to Morocco, the funny thing was after we got back my husband had a terrible rash! maybe that's what happened? wow, thanks for the info, cheers nell

Linda Crampton (author) from British Columbia, Canada on October 02, 2010:

Thanks for the comment. I’ve known about quinine for a long while, but I learned more about it when doing the research for this hub. That’s one thing I like about writing articles like this one – you always learn something new as you prepare the article!

Rebecca E. from Canada on September 26, 2010:

very interesting I'd never really heard of this drug.