Correlations have been calculated between high-density lipoprotein cholesterol and total plasma cholesterol, albumin, γ-glutamyl transpeptidase, aspartate aminotransferase, alkaline phosphatase, triglycéride, urea, creatinine and uric acid for diphenylhydantoin (DPH) users and for subjects attending a multiphasic health screening centre. For women DPH users, high-density lipoprotein levels correlated significantly with gamma glutamyl transpeptidase, cholesterol and alkaline phosphatase. These correlations were significantly different from those found for male DPH users and from subjects attending the health screening centre. In male DPH users, high-density lipoprotein cholesterol correlates negatively with urea and uric acid levels, a relationship which is found neither in women DPH users nor in the health screening centre population.