Chloroquine chemotherapy of malaria fever induces severe generalised pruritus in a large proportion of black Africans. In a double blind, placebo controlled, randomised, parallel group study in 28 historically chloroquine pruritus-reactor (R+) patients, with malaria, we evaluated the prophylactic and the palliative antipruritic actions of prednisolone (5 mg) or niacin (50 mg). There was a significant prophylactic effect of both drugs on the pruritogenecity of chloroquine as well as significant reduction in the area under the pruritus intensity-time curve, AUC(0-72 h) by niacin. The salutary effect both of niacin and prednisolone on chloroquine pruritogenecity resulted neither, in the mitigation of malaria parasite clearance, nor in the clinical amelioration following antimalaria therapy.