The aqueous leaf extract of Solanum erianthum collected in May was administered orally to albino Swiss mice infected with Plasmodium berghei berghei. The schizontocidal activity on early infection was assessed by administering the extract of S. erianthum, chloroquine, or distilled water as single daily dose from the day of infection for 4 days. Microscopic examination made on the fifth day from all the mice, showed S. erianthum extract producing a dose-related schizontocidal effect, with the highest having a chloroquine equivalent of 1.7 mg/kg. The residual activity of this extract was assessed by administering it to mice for 3 days prior to the day of inoculation with parasites. Seventy-two hours after infecting the mice, microscopic examination of the blood smears was made from all the mice. The extract produced dose-related activity. The highest dose and 1.2 mg/kg pyrimethamine produced 78.9 and 80.5% chemosuppression, respectively. Its effect on the established infection was studied by administering the drugs daily 72 h after infecting the mice, and for 5 days. The level of parasitaemia was assessed daily. The results show that the extract did not produce any significant suppression of infection. The observations are interesting and promising in view of the fact that the crude extract was used and also because controversy exists as to its usefulness as an anti-malarial agent.