The ethanolic leaf extract of Heinsia crinata, grown particularly for the leaf in Niger Delta region of Nigeria, was evaluated for antiplasmodial activity in Plasmodium berghei-infected mice as well as for hypoglycemic and antidiabetic activities in alloxan-induced diabetic rats. H. crinata (450-1,350 mg/kg/day) exhibited significant (P < .05) blood schizonticidal activity in both the 4-day early infection test and established infection with a considerable mean survival time, though not comparable to that of the standard drug, chloroquine (5 mg/kg/day). Treatment of alloxan-induced diabetic rats with the leaf extract caused a significant (P < .01) reduction in fasting blood glucose levels of normal and alloxan-induced diabetic rats both in an acute study and with prolonged treatment (2 weeks). The activity of the extract was comparable to that of the reference drug, glibenclamide, during the acute study but was not comparable to that of the standard drug during prolonged treatment. The results suggest that the leaf extract of H. crinata possesses significant (P < .05) antiplasmodial as well as hypoglycemic and antidiabetic effects that can be employed in health care.