An ambulatory monitor has been used to determine the characteristic patterns of tremor, sweating, skin temperature and locomotor activity in subjects undergoing alcohol withdrawal. Twenty-four hour records were obtained from six male subjects who had been consuming an average of 345 g of alcohol per day prior to cessation and from a group of age-matched controls. Consistent with earlier research and clinical observation, tremor, sweating and locomotor activity were elevated in withdrawal subjects. Sweating was greatest in the period from approximately 00.00 h to 06.00 h, as was skin temperature. Tremor and activity levels decreased during this period, but were considerably higher in withdrawal subjects. The data suggest that 24-h monitoring of alcohol withdrawal using objective methods provides a more sensitive assessment technique than the standard clinical approaches. The technique may be of value in other dysautonomic states.