I want to lose weight. I was advised to drink Tonic water because of its quinine content. Kindly let me know if this is a good idea. Ganiyat (by SMS) Quinine, a common ingredient in tonic water, can suppress appetite and cause weight loss, but it has a host of potential side effects and is an extremely toxic agent in overdose. Therefore, moderation is the key. 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 as well as weight loss. In the United States, the US Food and Drug Administration (FDA) limits the quinine content in tonic water to 83 ppm (83 mg per liter).