1. Chronic renal failure was induced in rats by surgical removal of thirteen-sixteenths of renal tissue.
2. The metabolism of p-amino[14C]benzoic acid was studied in the isolated perfused livers of control and chronically uraemic rats. There was a slower rate of clearance and decreased overall metabolism of the compounds in the uraemic rats.
3. Conjugation of p-amino[14C]benzoic acid with glycine and the formation of p-aminobenzoic acid glucuronide were both significantly decreased in the uraemic rats, but there was a significant increase in acetylation of both p-aminobenzoic acid and its glycine conjugate.