Skip to main content

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

Linda Crampton has an honors degree in biology. She is very interested in plant chemicals and their actions and benefits in 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 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.

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.