The effect of ethanol on the in vitro growth of the malaria parasite Plasmodium falciparum was investigated. 17 mM (0.08%) and 85 mM (0.39%) ethanol were added to parasite cultures and growth was determined for six days. A significant growth inhibition for both ethanol concentrations was observed on each day. It reached 65% for 85 mM ethanol after six days of incubation. Malarial parasites are strongly inhibited by ethanol concentrations which are attainable by extensive alcohol consumption.