This work aims to evaluate the antimalarial biological activities of medicinal plant extracts namely Artemisia annua, Alisicarpus ovalifolius and Securidaka longepediculata. The phytochemical analysis of the extracts of these plants revealed the presence of saponins, alkaloids, flavonoids, quinones, phenols and terpenes. Toxicity tests according to the method proposed by OECD have made it possible to conclude that the plant extracts are not toxic. The tests were carried out on mice, inoculated intraperitoneally with Plasmodium berghei. These animals were divided into eleven groups of five, nine of which each received a dose of the extract to be tested and the other two, distilled water for the negative control and arthemether for the positive control. The different extracts showed various antimalarial activities using the four-day Peters test on infected mice. Artemisia annua gave the highest parasitaemia reduction percentages with 87.2; 96.8 and 96% respectively at doses of 100, 250 and 500 mg/kg, while Alisicarpus ovalifolius recorded 61.6; 71.20 and 80.8% respectively at the same doses. Securidaka longepediculata extracts gave low percentage reductions in parasitaemia. Statistical analysis reveals that the extracts showed a significant difference compared to the negative control (P<0.05).