The resistance in human malaria is mainly of practical importance in relation to Plasmodium falciparum. Strains resistant not only to chloroquine but also to dihydrofolate reductase inhibitors, and even to potentiating combinations of these with sulphonamides or sulphones, are appearing in an ever increasing geographical area which now includes tropical Africa and India. Few new drugs are available or foreseen for the near future, mefloquine and artemisinine being the leading contenders. It is vital that all measures possible should be taken to protect such new compounds, their deployment in the form of judiciously selected combinations with other antimalarials being an essential procedure that should be followed. Drugs in new chemical classes and with different modes of action are still urgently needed. Reliance should not be placed on drugs alone to control malaria on a community basis.