Physiological tolerance

In physiology, tolerance occurs when an organism builds up a resistance to the effects of a substance after repeated exposure. This can occur with environmental substances such as salt or pesticides. It is also commonly encountered in pharmacology, when a subject's reaction to a drug (such as a painkiller or intoxicant) decreases so that larger doses are required to achieve the same effect.

See also

• desensitization
• drug tolerance
• tachyphylaxis