Ethanol is a drug that is classified as a general CNS depressant. Long-term exposure can result in tolerance and physical dependence. Ethanol consumption can affect the pharmacologic and therapeutic actions of prescription drugs, over-the-counter drugs, and illicit drugs. Ethanol-drug interactions have been reported to be the most frequent cause of drug-related medical crises in the United States. Alcohol misuse has a pervasive and potentially detrimental effect on the body from its point of entry through the gastrointestinal tract, to related organs such as the liver and the pancreas. The liver is one of the organs most significantly damaged and physiologically deranged as a result of alcohol ingestion. The two most common hepatic complications of alcoholism are hepatitis and cirrhosis. Cirrhosis was the seventh most common cause of death in the United States in 1975. Alcohol abuse interacts with physiological and metabolic processes of digestion to contribute to nutrient deficiency. Alcohol abuse has been suggested as the most common cause of vitamin and trace element deficiency in adults in the United States. Alcohol-derived nutritional deficiencies result in suboptimal health and are contributory to such abnormalities as anemia, convulsions, small-bowel dysfunction, and overt disorders such as Wernicke's encephalopathy. Brain dysfunction has been estimated to be present in from 50% to 70% of detoxified alcoholics entering treatment. Abstracting and adaptive abilities of social drinkers who had consumed no alcohol for 24 hours at the time of testing were found to be negatively associated with the amount of alcohol normally consumed per drinking occasion. Alcohol consumption alters numerous functions of the endocrine system, and excessive consumption has been implicated in impotency and early onset of postmenopausal amenorrhea. Recent evidence suggests that alcoholism may be a multifactorial genetically influenced disorder. In addition to genetics, social and environmental influences play significant roles. There is an association between alcoholism and depression in both men and women. Alcoholics often have high levels of depression and alcohol itself can increase depression. A disproportionately high number of people with drinking problems commit suicide, and more than a third of suicides involve alcohol. A propensity for suicide is thought to be associated with certain alcohol-related conditions such as depression, anxiety, mood fluctuations, and deteriorated social integration. Alcoholism has been associated with a number of adverse effects on the cardiovascular system, including a specific cardiomyopathy, low mean cardiac output, and depressed myocardial contractility. The drinking of large amounts of alcohol is associated with significant increases in blood pressure. Noncardiac myopathy has also been related to alcohol consumption. Heavy drinking increases the risk of cancer developing in the tongue, mouth, oropharynx, hypopharynx, esophagus, larynx, and liver. In the United States, these sites represent 6.1% to 9.1% of all cancer in the white population and 11.3% to 12.5% in the black population. In the broadest scope, alcohol abuse appears to be a risk factor in adverse fetal outcome. Fetal alcohol syndrome (FAS) has been identified among some children of alcoholic women. Fetal alcohol syndrome is characterized by CNS dysfunction, growth deficiency, a specific cluster of facial abnormalities, and other malformations, particularly skeletal, urogenital, and cardiac. It has been suggested that FAS is one of the leading causes of birth defects associated with mental retardetion. Short of the full complement of defects that characterize FAS, heavy alcohol use by women has been associated with birth anomalies. These effects of alcohol are independent of likely confounding variables, including smoking. Decreased birth weight is frequently associated with increased neonatal risk and has been observed among the children of women who consume an average of 30 mL of absolute alcohol per day (two standard drinks). Teratogenesis has also been noted in studies using alcohol-consuming animal models in whom the human condition is mimicked. Laboratory experiments have found that alcohol significantly impairs performance on sensory-motor and cognitive tasks at blood alcohol levels as low as 40 mg/dL. Such acute alcohol effects may contribute to other health hazards that may require medical treatment. For example, one third of all traffic fatalities are alcohol related; a significant number of industrial accidents, drownings, burns, and falls have been attributed to drinking; and a relatively high involvement of alcohol has been reported in assault, rape, child abuse and neglect, child molestation, and family violence in general. (<i>JAMA</i>1981;246:648-666)