Chemotherapeutic drugs available today are immunosuppressant, cytotoxic and with variety of side effects in cancer chemotherapy. Plant based immunomodulators are often an auxiliary therapy to overcome the repulsive effects of cytotoxic chemotherapeutic agents and to restore immunity with normal health. Mangroves Rhizophora apiculata (R. apiculata) extract was found to protect mice from cyclophosphamide (CTX) induced leukopenia. The leukocyte counts in the R. apiculata extract treated animals was significantly increased (10425 ± 163 mm³) where the control group shows no significant increase (7855 ± 282 mm³). The leukocytes count in CTX induced group treated with R. apiculata extract shows significant increase (5235 ± 303 mm³) when compared with CTX induced group (3416 ± 172 mm³) on the same day. The hemoglobin level of CTX induced group treated with R. apiculata extract shows increase in the level compared with the CTX induced animals. The bone marrow cellularity and α-esterase activity was also significantly higher compared to normal group and CTX induced group. Moreover, R. apiculata extract prevented the loss of organ weight and is increased the organ weight in treated animals. This indicates the efficiency of R. apiculata extract as an effective immunostimulant and better chemoprotectant against CTX induced toxicity in BALB/c mice.