A San Francisco Giants pitcher is suspended for 100 games after testing positive for a performance-enhancing substance.

According to a release from Major League Baseball, Guillermo Mota tested positive for Clenbuterol. The 100-game suspension is effective immediately.

Mota had a 50-game suspension in 2006 for a separate performance-enhancing substance violation.

According to Wikipedia, Clenbuterol is normally used by those with breathing disorders, like asthma, to increase aerobic capacity. It is only available with a prescription.