A sports drink is a beverage which is supposed to rehydrate athletes, as well as restoring electrolytes, sugar, and other nutrients. Sports drinks are usually isotonic, meaning they contain the same proportions of nutrients as found in the human body. The first sports drink was Gatorade. There is also another isotonic drink-Isostar, which is produced by a European company.

Sports drinks have their largest market in non-athletes. This is because many people like the sweet taste, and drinking sports drinks make them feel like they're athletes or being healthy (from the vitamins and minerals found in sports drinks). This has led some sports drinks to be targeted specifically at non-athletes, such as low-sodium or low-calorie sports drinks, although they are still marketed as being for athletes.

Sports drinks are different from energy drinks. Sports drinks are intended to replenish electrolytes, sugar, water, and other nutrients, and are usually isotonic (containing the same proportions as found in the human body). Energy drinks, on the other hand, simply provide lots of sugar and caffeine, with no healthful purpose.