An Ohio teen has died after consuming pure caffeine -- triggering a warning by the Food and Drug Administration.
The FDA warning tells consumers to avoid pure, powdered caffeine marketed as a dietary supplement on the internet.
One teaspoon is the equivalent of 25 cups of coffee.
Experts say the products are appealing to teens -- but many don't know you can overdose on caffeine.
Symptoms include rapid heart- beat, seizures, vomiting and disorientation.