The antimalarial activity of the Bolivian medicinal plant Pogonopus tubulosus (D.C.) Schumann was evaluated by in vitro testing on trophozoite stages of resistant and sensitive strains of Plasmodium falciparum and by in vivo tests on P. berghei send P. vinckei pefteri in mice. The bark of this medicinal plant yielded three alkaloids: tubulosine, psychotrine, cephaeline. Tubulosine showed an interesting activity in vitro with an IC50 of 0.006 μg/ mL against the sensitive strain of P. falciparum and an IC50 of 0.011 μg/mL against the resistant strain of P. falciparum. This compound had good in vivo antimalarial activity with an ED50 of 0.05 mg/kg/day on P. vinckei petteri strain and an ED50 of 0.45 mg/kg/day on P. berghei.