Tonic water is a soft drink containing quinine, which gives it a bitter taste. Quinine is a common treatment for malaria. Some people believe that it can also help with leg cramps and restless legs syndrome.

Quinine comes from the bark of the cinchona tree. This tree is native to central and South America, as well as some islands in the Caribbean and western parts of Africa.

People have consumed quinine in tonic water to help treat cases of malaria for centuries.

In this article, learn about what quinine is, its side effects, and possible benefits.

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Doctors continue to use quinine as a part of malaria treatment. However, it is typically a second-line treatment option and may have adverse effects at therapeutic doses.

Researchers cite the poor tolerability of the drug and the risk of severe health consequences as reasons to limit regular medicinal use.

As a food additive, quinine offers a bitter taste. Manufacturers usually add small amounts to tonic water.

Some people use tonic water to help treat nighttime leg cramps, but further research is necessary to prove its effectiveness and weigh this against the risk of side effects.

Experts consider quinine safe to consume in small doses. The United States Food and Drug Administration (FDA) has approved up to 83 parts per million in carbonated beverages.

The FDA also specifies that manufacturers must place quinine on the label for consumers to easily see.

Some people may experience allergic reactions to quinine. If this is the case, a person should avoid tonic water and any other products that contain quinine.

People who should avoid quinine in medications include:

Drug interactions

Some medications can interact with quinine. These may include:

The amount of quinine in tonic water is not likely to interact with a person’s medication or cause issues for people with the medical conditions listed above. However, people should speak with a doctor before taking medication or supplements containing quinine.

Why is quinine banned?

The FDA does not approve or recommend quinine as a treatment for certain health conditions, such as nocturnal leg cramps, due to the risk of adverse health complications, including:

Many unapproved products containing quinine do not state these risks in their safety information. However, the FDA approved three companies to use quinine in malaria treatments with a boxed safety warning.

Tonic water may provide the following benefits:

  • Some people believe tonic water helps with nocturnal leg cramps and restless legs syndrome.
  • Some people will enjoy the flavor of tonic water.
  • Drinking tonic water may help people stay hydrated.

Tonic water is a carbonated soft drink that may contain sugar and has little nutritional value. The quinine present in tonic water provides a distinctive bitter flavor.

While not dangerous, tonic water does not have any major benefits and could lead to an unnecessary increase in calorie consumption.

Quinine is very diluted in tonic water. The likelihood of a person experiencing any side effects from drinking tonic water is slim. However, side effects of quinine can include:

As a medication, quinine may have more severe side effects. Some of the possible side effects of taking quinine as a medication include:

People who regularly drink tonic water may also want to consider the extra sugar and calories that they are consuming. Soft drinks, including tonic water, have little nutritional value but contribute to a person’s daily calorie intake.

What does quinine do in the body?

As a malaria medication, quinine kills the parasite that causes malaria. In small doses, such as in a single glass of tonic water, quinine has little effect on the body, and the FDA considers it safe.

What is quinine in tonic water good for?

Quinine gives tonic water its bitter taste, which some people enjoy.

Tonic water’s original marketing from 1862 claimed: “It’s properties are antacid, cooling, and refreshing…it gives strength to the stomach and tone to the whole nervous system, and is especially adapted to persons feeling depressed from mental or bodily excitement.” There is no scientific evidence to support these claims.

The quinine in tonic water helps give it a bitter taste. People should not mistake tonic water for a healthful drink, as it may contain sugar and provides no additional nutritional value.

The quinine in tonic water is very diluted. Some people claim tonic water may help with leg cramps, but this usage is not FDA-approved, and further research is necessary.

It is unlikely that a person will experience even mild side effects from drinking tonic water, but they should be cautious if they are taking quinine as a medication and try to report any side effects to a doctor.