The objective of the study was to prove the potential extract of Syzygium cumini L leaf and stem bark as an adjuvant to malaria modelling mice. Antimalarial effects were assessed by the percentage of parasitemia, growth inhibition, 50% dose level (ED50), Parasite Clearance Time (PCT), Recrudescence Time (RT) of Plasmodium berghei. Male albino Swiss mice infected with 1x105 P. berghei parasite in 0.2 ml intraperitoneally. Treatment with chloroquine 25 mg/kg body weight, chloroquine combination 25 mg/kg body weight with leaf and stem bark extract of Syzygium cumini L dose 600 mg / kg body weight for 4 days and 24 hours after infection, and then its activity as antimalarial and adjuvant therapy were observed. The results showed that the extract of Syzygium cumini L leaf combined with chloroquine gives highly significant result in inhibiting the growth of parasites than the chloroquine alone and the extract of Syzygium cumini L leaf combined with chloroquine gives the Parasite Clearance Time faster and Recrudescence Time (RT) longer than the other treatment.