Tonic Water - Quinine Content

Quinine Content

Medicinal tonic water originally contained only carbonated water and a large amount of quinine. However, most tonic water today contains a less significant amount of quinine, and is thus used mostly for its flavour. As a consequence, it is less bitter, and is also usually sweetened, often with corn syrup or sugar. Some manufacturers also produce diet (or slimline) tonic water, which may contain artificial sweeteners. Traditional-style tonic water with little more than quinine and carbonated water is less common, but may be preferred by those who desire the bitter taste.

In the United States, the US Food and Drug Administration (FDA) limits the quinine content in tonic water to 83 ppm (83 mg per litre if calculated by mass), while the daily therapeutic dose of quinine is in the range of 167–333 mg. Still, it is often recommended as a relief for leg cramps, but medical research suggests some care is needed in monitoring doses. Because of quinine's risks, the FDA has declared nonprescription sources, such as tonic water, should not be used to prevent or treat leg cramps.