Definitions of Delirium Tremens (DT) and related clinical states are discussed together with the concepts of aetiology and pathogenesis in relation to psychiatric disease. The withdrawal theory which considers reduction or cessation of alcohol intake as an important precipitating factor in DT is discussed; this theory is supported by experimental studies of ethanol withdrawal in man and by studies indicating cross dependence between ethanol and several other CNS depressors; the arguments in the literature for and against the withdrawal theory are discussed. Other possible aetiological factors such as type of liquor, hypovitaminosis, liver disease, dysfunction of the adrenals and fat emboli are reviewed, and it is concluded that these factors are unimportant as precipitating or specific aetiological factors in DT. Possible pathophysiological mechanisms are discussed, especially concerning electrolyte metabolism and cerebral blood flow and oxygen consumption. It is concluded that the pathophysiology of the disease is poorly understood, and some possibilities for future research are indicated. The discussion about treatment of DT is concentrated on drug treatment, and the literature concerning antipsychotics and sedatives is reviewed. It is concluded that barbital, a long-acting barbiturate, is the most effective treatment; diazepam can be recommended as an acceptable alternative. Finally, practical recommendations concerning treatment are given.