AbstractThe antimalarial activity of an ethanol leaf extract of Setaria megaphylla was studied in vivo in mice infected with Plasmodium berghei berghei during early and established infections. Setaria megaphylla (100–300 mg/kg/day) exhibited a significant (p < 0.05) blood schizonticidal activity in 4‐day early infection and in established infection with a significant (p < 0.05) mean survival time comparable to that of the standard drug, chloroquine, 5 mg/kg/day. The leaf extract possesses a promising antiplasmodial activity in vivo which can be exploited in malaria therapy. Copyright © 2007 John Wiley & Sons, Ltd.