A study was carried out to investigate the chemotherapeutic effects of diminazene aceturate (Berenil®) and melarsamine hydrochloride (Cymelarsan®) on the alteration of biochemical parameters in red-fronted gazelles experimentally infected with Trypanosoma brucei. A significant (P 0.05). These biochemical alterations were effectively modulated to preinfection levels before the end of the experiment in gazelles treated with either 0.3 or 0.6 mg/kg body weight (BW) of Cymelarsan, or 7.0 mg/kg BW of Berenil. The results therefore suggested that an initial stress associated with an increased serum cortisol level and its immunosuppressive effect might have been responsible for the establishment and clinical manifestation of the infection in the gazelles. Furthermore, the severity of the biochemical effects experimentally induced indicated that trypanotolerance in wild gazelles could be compromised, especially when they are subjected to the stress of captivity. Results also showed that Cymelarsan at 0.3 or 0.6 mg/ kg BW, and Berenil at 7.0 mg/kg BW were effective in managing the disease under experimental conditions.