In a patient with longstanding severe uraemic pruritus who was undergoing chronic haemodialysis cholestyramine caused the pruritus to disappear completely within a few days. A four-week randomised controlled double-blind study was therefore performed in 10 other patients with uraemic pruritus who were on chronic haemodialysis. The pruritus improved considerably in four of the five treated patients, whereas only one of those treated with placebo experienced relief. The patient who had no relief while on cholestyramine showed a considerable improvement when the dose subsequently doubled. One of the five patients receiving cholestyramine experienced mild and easily reversible constipation, and another suffered nausea. Neither of these complications prevented the patients from continuing treatment. Cholestyramine seems to be useful in treating uraemic pruritus, although it is not known how it acts.