The clinical utility of standard liver function tests for monitoring low dose pulse methotrexate therapy is reviewed in 163 rheumatoid arthritis patients over an eight-year period. Abnormalities of hepatic enzymes were seen in 58% of patients but led to cessation of therapy in only 5%. Moderate alcohol intake did not affect the frequency of liver test abnormalities. Abnormalities were seen more frequently in patients with longer duration of methotrexate therapy and in those with higher total dose. There was no correlation between liver test abnormalities and day of serum sampling relative to day of methotrexate dosing, nor was a correlation seen between liver test abnormalities and total weekly dose of methotrexate. Methotrexate has been demonstrated to be an effective drug in the treatment of rheumatoid arthritis. The clinical utility of standard liver tests to predict the potential for hepatotoxicity is questionable.