People with bad kidneys try to drink less Red Bull, also known as Red Bull vitamin functional drink, which contains taurine, caffeine, niacin, vitamin B6, pantothenic acid, vitamin B12, fructose, glucose. Because it contains a lot of caffeine, it is often used as a refreshing and fitness drink. Caffeine is a xanthine alkaloid compound that is a central nervous stimulant and is widely used as a refreshing item. But caffeine has many hazards; its a carcinogenic agent, and in 2017 the World Health Organization listed it on its list of carcinogens. After a one-time intake of a large amount of caffeine can cause symptoms such as hypersensitivity, anxiety, anger, etc., and in serious cases can induce life-threatening. If your kidneys are not so good, it is recommended to drink less functional drinks, which can be a burden to your kidneys.