Abstract:SKF 525‐A at concentrations from 10−5M to 2 × 10−4M inhibits the glucuronidation ofp‐aminophenol (PAP),p‐nitrophenol (PNP), and bilirubin by a clonal strain of rat hepatoma cells (MH1C1) grown in culture. At higher concentrations of SKF 525‐A the glucuronidation of PAP and PNP in a homogenate system from the cell cultures and normal rat liver is also inhibited, PAP to the greatest extent. The inhibition of PAP glucuronidation in the homogenate system appears to be of the non‐co