The efficacy of chlorpheniramine in the prevention of choroquine-induced pruritus was assessed in a trial involving 132 malaria patients with a history of chloroquine-induced pruritus. Patients who gave informed consent were randomized into either placebo or treatment group. 70 were randomized into chlorpheniramine group and 62 into placebo group. Of the 70 patients put on chloroheniramine, 52 (74%) did not develop pruritus while only 15 (24.2%) of the 62 patients put on placebo did not develop pruritus. Chlorpheniramine was significantly more efficacious in preiritus prevention than placebo (X2 = 31; p less than 0.001). The protection rate of chlorpheniramine against chloroquine-induced pruritus was 67%. The number of patients who terminated treatment prematurely was significantly higher in placebo group than in piriton group. The possibility of recommending the drug into malaria treatment schedules for individuals with known history of chloroquine-induced pruritus is discussed.