The very limited number of compounds available, the lack of prospects for the development of new products and the emergence of resistance are arguments for the use of therapeutic combinations. Ideally, drug combinations should allow for reductions in the dosages of the drugs used in a way that, in particular in the case of toxic drugs such as those used for second stage HAT, the toxicity of the combination does not exceed that of either monotherapy. Of the three drug combinations nowadays possible: melarsoprol-nifurtimox, melarsoprol-eflornithine and eflornithine-nifurtimox, the last one has (in two different dosing regimens) shown the least treatment-associated toxicity and mortality in the 69 patients treated in one previous and this clinical trial to date. Good tolerability was also observed in a case series of 31 patients. The efficacy data to date suggest that efficacy is comparable to that of eflornithine and that of melarsoprol (in areas without high melarsoprol failure rates).