Fifteen extracts from nine selected Argentine medicinal plants were tested for their antiplasmodial activity in vitro by assessing their ability to inhibit the uptake of [3H]-hypoxanthine into the Plasmodium falciparum K1 pyrimethamine/chloroquine resistant strain. The methanol extract of Satureja parvifolia showed good antiplasmodial activity (IC(50) 3 microg/ml). Inhibition of the growth of P. falciparum was also observed with aqueous extracts of Buddleja globosa and S. parvifolia.