The racers have a duty to treat their dogs humanely, and performance enhancing substances are strictly forbidden.

Other studies have looked at improving intelligence and preventing cognitive decline by using cognition enhancing substances known as nootropics.

On August 1, 2005, Palmeiro tested positive for performing enhancing substances and was suspended ten days.

Q. Could we see an article on Babe Ruth, the asterisk, and the consumption of illegal performance enhancing substances?

As of December 19, 2008, the Code banned 192 performance enhancing drugs, substances, and methods.

Kenny Williams admitted to and tested positive for performance enhancing substances in November, 2009.

Those who use performance enhancing substances were called cheaters, cowards, bad examples for the nation's children.

He stated that this was a one-time purchase, and that he never used performance enhancing substances.

In 1995 the Chinese People's Daily newspaper published an anti-doping policy and proclaimed an official prohibition on performance enhancing substances.

Worre tested positive for performance enhancing substances in 1992, he confessed to the use of doping, receiving a conditional suspension.