In endemic zones, more especially in Africa, the treatment is given following a clinical diagnosis, where the major symptom is a fever. If it is completely justified, this presumptive treatment of a febrile crisis does not provide a fully satisfactory solution: this attitude leads to the prescription of unjustified treatments for non-malarial fevers and increases the medicinal pressure exercised on the parasite. Furthermore, the chemoresistance of Plasmodium falciparum imposes therapeutic choices with less well-tolerated and much more expensive molecules than chloroquine. Resistance to these new molecules may also develop rapidly, if they are not used judiciously. Only evidence of the parasite may provide a sure diagnosis and lead to appropriate treatment.