As researchers continue to study the benefits and harms of caffeine, more manufacturers than ever are adding this essentially psychoactive drug to a wide range of foods, beverages and products.

The popular stimulant is found in tea, coffee, chocolate, many soft drinks, pain relievers and even topical beauty products, so beware, warns the Food and Drug Administration.

In addition, because caffeine may turn up in such unexpected foods as jelly beans, waffles, gum and syrup, it’s easy to exceed the maximum amount recommended by the FDA: 400 milligrams per day for adults, the amount in four or five cups of coffee.