Quinine is a type of alcohol, first derived from the bark of a cinchona tree in the 19th century. It serve numerous medicinal purposes, like treating cramps and malaria. If used improperly, however, the product can seriously endanger people's health and can even lead to death in some extreme circumstances. The FDA has banned it, though it still appears in small amounts in tonic water. While drinking large amounts of tonic water entails few risks, some people still can react badly.
Thrombocytopenia, a type of blood disorder, can lead to haemorrhage and clotting problems, which can in turn cause death if quinine is involved. The condition appears very infrequently, and rarely constitutes a serious concern for people drinking tonic water with quinine. However, those susceptible to the disorder should avoid tonic water with quinine at all costs: even small amounts can cause serious illness and even death. Doctors can test you for your susceptibility to quinine and Thrombocytopenia, to see if a danger exists.
Cinchonism consists of other symptoms which come from ingesting quinine. This usually stems from actual quinine tablets which people take to prevent or relieve malaria symptoms in the Third World, though rarely from drinking tonic water. However, if you consume enough tonic water or are extremely susceptible to quinine in your body, you can suffer from a variety of symptoms like dizziness, headache, nausea, ringing in the ears, blurred vision and disturbances in colour perception. If this occurs, drink regular water until the symptoms pass and the quinine flushes from your system.
Some people are allergic to quinine, which can cause a number of different hypersensitivity reactions due to exposure to the drug. They include rashes and other breakouts on the skin, sores, itching and even swelling to certain areas. Hypersensitivity may also result in changing heart rhythms, which can cause shortness of breath and lead to the milder symptoms of cinchonism.