A woody vine native to the Amazon.  Guarana prevents drowsiness and may reduce the risk of heart attacks.  However, a cup of guarana contains three times more caffeine than a cup of coffee.  People in South America either chew a spoonful of the seeds or crush the seeds with a mortar and pestle and add a bit of water to mix up a paste. The dried paste is then used to make a hot beverage like coffee.

Guarana may have the ability to keep your red blood cells moving when they have a tendency to clump together and trigger a heart attack according to a laboratory study conducted at the University of Sao Paulo in Brazil.  However, further studies are needed.  Guarana may hold potential as a heart protector but, it's still too soon to recommend it.