Trypanosomosis is an infectious disease with great economic impact on livestock production. In this study, the effects of probiotic on serum biochemical changes of Nigerian indigenous dogs experimentally infected with Trypanosoma brucei brucei were investigated. Twenty (20) healthy dogs of both sexes (6–10 kg body weight) following screening, were randomly divided into 5 groups of 4 dogs each. Dogs in group I (uninfected and untreated); group II (uninfected + multi species (Pet dophillus®) probiotic); group III (infected + multi species probiotic); group IV (infected + diaminazene aceturate); and group V (infected + probiotic + diminazene aceturate). Dogs were fed probiotic for 21 days before infection, and up to the last day post-infection (PI). Dogs in infected groups were inoculated intraperitonially with 2.5 × 10(6) trypanosomes on day 21 and diminazene aceturate was administered on day 5 post-infection (PI). Prepatent period and parasitaemia were determined. Blood was collected in plain sample bottles and serum harvested for serum biochemical analyses. Prepatent periods of T. brucei brucei were 4.75 ± 0.25 days (group III), 4.00 ± 0.41 days (group IV) and 4.25 ± 0.49 days (groups V); and parasitaemia was significantly decreased (P 0.05) differences existed in the mean serum albumin and creatinine levels in all groups of dogs. The mean serum activities of alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) were increased significantly (P