Caffeine - Wikipedia The most common sources of caffeine for human consumption are the tea leaves of the Camellia sinensis plant and the coffee bean, the seed of the Coffea plant Some people drink beverages containing caffeine to relieve or prevent drowsiness and to improve cognitive performance
Caffeine: How much is too much? - Mayo Clinic Up to 400 milligrams (mg) of caffeine a day seems safe for most adults That's about the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two "energy shot" drinks Keep in mind that the caffeine content in drinks varies widely
Caffeine | Stimulant, Health Benefits, Addiction | Britannica Learn about caffeine's effects on the human body Caffeine has a stimulating effect on the central nervous system, heart, blood vessels, and kidneys It also acts as a mild diuretic Caffeine’s potent stimulatory action makes it a valuable antidote to respiratory depression induced by drug overdose (e g , from morphine or barbiturates)
Caffeine - The Nutrition Source Although we tend to associate caffeine most often with coffee or tea, the research below focuses mainly on the health effects of caffeine itself Visit our features on coffee, tea, and energy drinks for more health information related to those beverages
Caffeine: Benefits, risks, and effects - Medical News Today Caffeine is a stimulant and the most commonly used drug in the world Benefits can include increased alertness, energy, and concentration However, it can also lead to insomnia and headaches
Caffeine - MedlinePlus Many people enjoy a cup of coffee or tea to give them a boost But is it safe? Learn more about caffeine