A placebo-controlled trial of Levamisole in 47 black children with measles is reported. The children were of satisfactory nutrition but at risk from severe disease as judged by a lymphopenia of less than 2000 X 10(-9)/m3 (less than 2000/mm3) early in the exanthem. A placebo or Levamisole (2.5 mg/kg/dose) were given orally weekly for six weeks. Death or persistence of radiological pneumonia at six weeks occurred in 74% of the Levamisole and 92% of the placebo group. No side effects of the drug were noted. The immune responses that were monitored for six weeks were total lymphocyte and lymphocyte subpopulation counts, PHA stimulated lymphocyte transformation, leucocyte migration inhibition, measles antibody titres and serum levels of immunoglobulins and complement components. In none of these was a significant difference found between the two groups. While there was a trend clinically towards complete recovery in the group that received Levamisole, statistically it was not significant, and therefore Levamisole cannot be recommended for treatment of measles.