Combination therapy is essential to safeguard existing and future antimalarial drugs, prompting exploration into adjuvant therapies for managing cerebral malaria. This study aimed to assess the effectiveness of Annona muricata leaves extracted by water (AME) as an adjuvant for Artemisinin-based combination therapy (ACT) in mice infected with Plasmodium berghei ANKA (PbA) malaria. The research employed a Post Test Only Control Group Design for the study. A few of 24 Swiss mice were subjected to various treatments, including AME, ACT, and their combination, with a focus on host survival, lymphocyte generation, and migration. Results demonstrated that mice treated with the combination of AME and ACT exhibited significantly reduced parasitemia, and lower percentages of splenic lymphoblasts compared to control groups. Specifically, the mean percentage of splenic lymphoblasts in the AME and ACT combination group was substantially lower than in the control groups and individual treatment groups. Parasitemia levels were significantly reduced in the combination group, emphasizing the synergistic effect of A. muricata and ACT. In conclusion, A. muricata demonstrated a superior impact on parasitemia, and splenic lymphoblasts in malaria mice treated with ACT, highlighting its potential as a valuable adjuvant therapy in the fight against malaria.