The Hidden Ingredient In Tonic Water You Should Know About

Here's a fun party trick: Place a gin and tonic under a black light, and like magic you have a glowing beverage. Quinine, the compound that gives tonic its bitter flavor, contains phosphors that emit UV light that makes it glow blue. And interestingly, quinine is good for more than just creating a neon drink. It has been historically crucial for treating malaria, saving countless lives, and was available as an over-the-counter treatment for leg cramps. It has since been banned due to side effects, which even called into question the safety of quinine-containing products like tonic water. So if your go-to drink is a gin and tonic, you love sipping on tonic water with lime during the summer months, or you love bitters, here's everything you need to know about this medicinal-compound-turned-beverage.

Quinine has a distinct bitter flavor that many found almost unpalatable, making it hard to enforce patient treatment compliance. To dilute the flavor, water and sugar were added, and tonic water was born. The British Army stationed in India regularly rationed this antimalarial concoction throughout the 19th century in an attempt to treat and prevent malaria. Legend has it that British generals, eager to further improve the taste of the bitter beverage, began mixing their daily tonic water with gin, inventing the classic cocktail: gin and tonic.

Although it was still not entirely understood how quinine combats malaria, it continued to be the primary medication for malaria until the mid-20th century—despite the fact that it's not 100 percent effective, it was found to cause a combination of unpleasant side effects, coined cinchonism3, which include nausea, vomiting, vertigo, headaches, and in more serious cases, deafness. Fortunately, scientific discoveries in the 20th century led to the development of safer and more effective drugs for malaria. However, quinine, in the form of tablets or injections, is still used as an alternative treatment, especially when combating antibiotic-resistant strains of malaria or when more expensive new treatments are not available.

In the early 20th century, quinine started being used for a new medicinal purpose: the treatment of leg and muscle cramps. Although some studies have found quinine may decrease the intensity and frequency of cramps, others concluded the benefit is minimal4. Nevertheless, quinine tablets were available over the counter until 2006, when the FDA5 began restricting their availability due to the risk of serious side effects. The FDA reported that prolonged quinine exposure could lead to liver damage, low platelet levels, and internal bleeding. In one study6 it was found that quinine use for the treatment of leg cramps even increased the risk of death from all causes in patients. Quinine is still available by prescription, but there are many safer alternatives for the treatment of leg cramps, including magnesium, stretching, and vitamin E, that should be exhausted before turning to this risky medication. The only FDA-approved medicinal use of quinine is for the treatment of malaria.

Looking for a refreshing cocktail recipe? Check out this matcha mojito.