Flow cytometry for the intracellular detection of T-cell cytokines was performed for 15 Gabonese patients during acute uncomplicatedPlasmodium falciparum malaria. A striking expansion of CD4⁺ and CD8⁺ T cells producing gamma interferon (IFN-γ) was found during drug-induced clearance of parasitemia, paralleled by a decrease of interleukin-2 (IL-2) production. The frequency of IL-4- and IL-13-producing CD4⁺cells gradually decreased, whereas the frequency of T cells producing IL-2⁺–IFN-γ⁺, IL-4⁻–IL-5⁺, and IL-4⁺–IL-5⁺ cytokines as well as IL-4⁺–IFN-γ⁺ and IL-13⁺–IFN-γ⁺ cytokines was not significantly altered. The capacity for IL-10 production within the CD4⁺ subset increased due to an expansion of both IL-10⁺–IFN-γ⁻ and IL-10⁺–IFN-γ⁺ cytokine-expressing cells. Thus, a more pronounced Th2-driven immune response during acute untreated P. falciparum infection with a shift towards Th1 responsiveness induced by parasite clearance is suggested.