Abstract: The modulatory activity of methanolic seed extracts of Garcinia kola (ME) on Delayed-Type Hypersensitivity (DTH) response, primary and secondary humoral responses and on in vivo leucocytes mobilisation were evaluated. Acute toxicity test of the extract was also carried out. The ME at 250 and 500 mg kg-1 body weight produced significant (p<0.05) inhibition of DTH response in mice by 67.40 and 53.29%, respectively. Primary and secondary sheep red blood cells-specific antibody titres were significantly elevated when compared to the control group. Agar-induced in vivo leucocytes mobilisation into the mice peritoneal fluid was significantly (p<0.05) increased by ME at 250 and 500 mg kg-1. The total leucocytes counts were higher in the extract-treated groups when compared to the control group. The mobilised white blood cells were predominantly polymorphonuclear neutrophils (PMNs). The ME administered (orally) at 5000 mg kg-1 did not caused lethality and signs of acute intoxication after 48 h observation period. The results of this study have established cellular and humoral immunomodulatory activities of G. kola extract and justify further investigations into the effects of specific constituents of the plant on immune system components.