In general, intoxication refers to a condition in which a person's physiologic state is altered, usually impaired, by an outside substance. This disturbance of the person’s normal state is triggered by exposure to drugs or alcohol. The intoxication state can also be called drunk, stoned or high.

Intoxication may result in changes in a person’s cognition, perception, judgment, or behavior. The person’s physical abilities and level of consciousness may also be affected. Usually, intoxication is triggered by the use of drugs or alcohol by the individual. The amount of intoxicants necessary to trigger the effects of their use will depend on the individual’s physiological condition and tolerance levels. In criminal proceedings, intoxication may have a legal definition that requires a specific measurement, such as a blood alcohol level. If the individual tests at or above the legally defined level, he or she will be deemed to be intoxicated even if there is no visible evidence of impairment.