Recent studies on resistance to blood schizontocides in Plasmodium falciparum give a rational basis for the use of artemisinins combined with arylaminoalcohols for the treatment of uncomplicated chloroquine-resistant malaria in Africa. In areas where such combinations are introduced, there is reason to believe that the continued use of chloroquine in the community will help protect the new drugs from resistance. In view of several laboratory studies, combinations of artemisinins with antifolates or chloroquine pose a risk of antagonistic interaction. This can be avoided by use of the artemisinin and the companion drug sequentially.