Plasma adrenocorticotrophic hormone (A.C.T.H.) levels were estimated by radioimmunoassay in 20 male chronic alcoholics (mean age +/- SD - 40.55 +/- 7.83) both before and during treatment with chlormethiazole. There was no statistically significant difference between the pre-treatment (mean +/- SD =25.25 +/- 14.87 ng/1) and post-treatment levels (mean +/- SD = 26.45 + 15.32) of plasma A.C.T.H. (paired "t" = 1.83; N.S; log transform "t" = 2.79; N.S; p less than 0.05). So, chlormethiazole has not been found to influence plasma A.C.T.H. levels adversely but because of its sedative effect, it may eliminate the ethanol-induced stress thereby helping indirectly in reducing the elevated levels. Plasma A.C.T.H. levels seem to be raised in some patients due to chronic ethanol ingestion and total abstinence for more than a week might be needed for the raised levels to return towards normal diurnal pattern.