Colesevelam is an anion-exchange resin with a 7-fold higher bile acid-binding capacity and fewer side effects than cholestyramine, the current first-line treatment option for cholestatic pruritus. The aim of this trial was to compare the effects of colesevelam and a placebo in patients with cholestatic pruritus. In a randomized, double-blind, investigator-initiated, multicenter trial, patients with cholestatic pruritus, both treatment-naive and previously treated, received 1875 mg of colesevelam or an identical placebo twice daily for 3 weeks. The effect on pruritus was assessed with daily visual analogue scales, quality-of-life scores, and evaluations of cutaneous scratch lesions. The predefined primary endpoint was the proportion of patients with at least a 40% reduction in pruritus visual analogue scale scores. Thirty-eight patients were included, and 35 were evaluable: 17 took colesevelam, 18 took the placebo, 22 were female, 8 were treatment-naive, 14 had primary biliary cirrhosis, and 14 had primary sclerosing cholangitis. The mean serum bile acid levels were comparable between the groups before treatment (P = 0.74), but they were significantly different after treatment (P = 0.01) in favor of patients treated with colesevelam. Thirty-six percent of patients in the colesevelam group reached the primary endpoint versus 35% in the placebo group (P = 1.0). There were no significant differences between the groups with respect to pruritus scores, quality-of-life scores, and severity of cutaneous scratch lesions. Mild side effects occurred in one colesevelam-treated patient and four placebo-treated patients. CONCLUSION: Although colesevelam significantly decreased serum bile acid levels, this trial was unable to demonstrate that it was more effective than a placebo in alleviating the severity of pruritus of cholestasis.