Abstract: The effect of Nigella sativa (black seed) oil based diet on the management of Trypanosoma brucei infected rats was investigated. Prasitaemia was monitored and haematological and enzymatic studies were carried out on liver and blood of infected rats fed with diet formulated with black seed oil (treatment). Comparison was made with untreated infected rats and uninfected rats. The diet formulated with black seed oil extended the life span for 7 and 5 days for prophylactic and early stage feeding, respectively while the late stage feeding extended it by a day. The T. brucei-infection significantly (p<0.05) increased liver Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT) and Gamma Glutamyl Transaminase (GGT). Serum GOT and GPT specific activities were also significantly (p<0.05) increased. However serum GGT activity showed no significant (p<0.05) difference in all the rat groups. While haemoglobin concentration, white blood cells, red blood cells, pack cell volume, mean cell haemoglobin concentration and platelet were significantly (p<0.05) reduced, as observed in the control and late stage feeding, by the infection, prophylactic and early stage feeding with diet formulated with N. sativa oil significantly (p<0.05) improved the parameters towards those obtained in uninfected rats. We concluded that the N. sativa oil used in formulated diet could be involved in the improvement of the pathologic events observed in the T. brucei infected rats with prophylactic and early stage feeding.