Health care professionals indicate that caffeine appears to be safe for the majority of healthy adults when it's consumed in moderation. The Mayo Clinic notes that up to 400 milligrams of caffeine per day, which is roughly equivalent to the amount found in four cups of coffee, is considered safe for most healthy adults.

However, individuals should be careful of certain forms of caffeine–caffeine in powder or liquid form can provide toxic levels of the stimulant. A single teaspoon of powdered caffeine can contain as much of the stimulant as 28 cups coffee. That much caffeine can contribute to serious health problems and possibly death.