Intoxication is a transient condition that follows the administration of alcohol or a psychoactive substance and results in disturbances in the level of consciousness, cognition, perception, judgment, affect or behavior, or other psychophysiological functions and responses.
The disturbances are related to the acute pharmacological effects of, and learned responses to, the substance. They resolve over time with complete recovery, except where tissue damage or other complications have arisen.
The term is most commonly used with regard to alcohol use: its equivalent in everyday language is "drunkenness." Alcohol intoxication is manifested by such signs as facial flushing, slurred speech, unsteady gait, euphoria, increased activity, volubility, disorderly conduct, slowed reactions, impaired judgement and motor incoordination, insensibility, or stupefaction.

Intoxication is highly dependent on the type and dose of drug and is influenced by an individual's level of tolerance and other factors. Frequently, a drug is taken in order to achieve a desired degree of intoxication. The behavioral expression of a given level of intoxication is strongly influenced by cultural and personal expectations about the effects of the drug.

Acute intoxication is usually closely related to dose levels. Exceptions to this may occur in individuals with certain underlying organic conditions (e.g., renal or hepatic insufficiency) in whom small doses of a substance may produce a disproportionately severe intoxicating effect. Disinhibition due to social context should also be taken into account.
Acute intoxication is a transient phenomenon. Intensity of intoxication lessens with time, and effects eventually disappear in the absence of further use of the substance. Recovery is complete except where tissue damage or another complication has arisen.

World Health Organization. Management of substance abuse. Internet. Accessed on January 20, 2016.