<p> Methotrexate had been suspected to be harmful to the liver in psoriatic patients. The data of a prospective study to find out whether the drug affected the acquisition and worsening of various liver pathology was analysed. Personal particulars which would have adverse effect on the liver were also investigated. Log-linear models were fitted to this set of categorical data in the form of multidimensional contingency tables. It was found that methotrexate would be hepatotoxic if the drug was taken over a prolonged period and/or if the cumulative dose taken was large. Otherwise, methotrexate could be administered to psoriatic patients without causing much harm to the liver.</p> / Thesis / Master of Science (MSc)