Quinine

Studies in people

• No harm found

  How the body handles medicines²

  Quinine in tonic water did not change how the body broke down a common medicine in this study.

• Concern

  Brain and nerve effects⁵

  Some people report confusion, seizures and coma after drinking quinine in tonic water and bitter lemon.

• Concern

  Balance and eye reflexes⁷

  People who drank tonic water with quinine daily showed brief changes in balance tests at the higher amount.

Single cases of misuse or overdose

One person or one incident, such as an accidental overdose or a mistake in a kitchen or factory. They are real, but a single case does not show what happens at normal amounts, so the signal does not count them.

• Skin reaction to a drink³

  A man's red skin patches returned after quinine in tonic water.

• Skin rash from drinks⁴

  In two people, red skin patches came back in the same spots after they drank tonic water with quinine.

How it’s made and used

• Appetite and hunger⁶

  In people, quinine by mouth or into the stomach lowered desire to eat and hunger, but people ate the same amount.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.