Leucocyte ascorbic acid (LAA) levels were measured in 138 patients with liver disease. Significantly reduced levels were found in 37 patients with alcoholic liver disease (P less than 0-01) and 25 patients with primary biliary cirrhosis (P less than 0-05). In the primary biliary cirrhosis patients, cholestyramine therapy was associated with significantly lower levels of the vitamin (P less than 0-05). Liver ascorbic acid measured in Menghini needle biopsies in 20 patients was significantly correlated with LAA (r=0-807, P less than 0-001). No significant correlation was found between LAA and haematological indices, conventional liver function tests, or cholesterol levels in any group of patients. Patients with LAA levels below 100 nM/10(8) WBC had significantly higher antipyrine half-lives (mean=28-3 h) than patients with LAA levels above this level (mean=18-6 h) (P less than 0-05). Delayed drug metabolism related to low LAA should be considered when drugs metabolised by the liver are prescribed for patients with alcoholic liver disease or primary biliary cirrhosis.