VIAGRA

New York Yankees pitcher Roger Clemens, who was recently outed by a New York tabloid for using Viagra to increase his performance on the field, is among many professional athletes who make unorthodox use of pharmaceutical drugs.

(ABCNews Photo Illustration)

Experts believe athletes and performers use a strange and alarming array of methods to keep themselves competitive in two of the most competitive careers in America, often at their own peril.

Although it may seem counterintuitive, Viagra -- which Major League Baseball does not prohibit -- works by relaxing muscles and increasing blood flow through the body.