The use of herbs and plant materials have always been popular in the treatment of febrile illness, and it has grown over time in malaria endemic areas. Structured questionnaires were administered in four towns in each of the three senatorial districts of Ondo state to know the most commonly used herbs and the results suggested Mango (Mangifera indica) Siam weed (Chromolaena odorata) and Guava (Psidium guajava) as most preferred by the people. An in vivo experiment was conducted to validate the efficacy of the mentioned plants. Mice weighing between 45-50g were inoculated with Plasmodium berghei and left for 28days, they were examined on day 7, 14, 21 and 28 to monitor the parasitaemia level, mice were treated with the herbs at different concentrations of 0.01, 0.05 and 0.1%, each having three replicates. The herbs efficacies were examined 4, 8 and 12 days after treatment. The suppressive effects of the herbs showed that at 0.01% concentration, Siam plant extract had the lowest antiplasmodial effect with 44.43% clearance rate, while the extracts of the three herbs combined had the highest efficacy of 61.13%. At the highest concentration (0.1%) Guava leaf extract had the lowest efficacy 72.23% while the extract of the three herbs combined had the highest suppressive effects 90.30%. The results showed that the treatments were dosage dependent and combinations of the herbs showed synergistic efficacies.

Keywords: Antiplasmodial, Plasmodium berghei, Chromolaena odorata, Psidium guajava, Mangifera indica), Synergy