To be efficient in Chagas disease (Chd) a drug  must have effect on the amastigotes forms of Trypanosoma cruzi (T. cruzi), in other  words on the intracellular  reproduction parasites in the mammals animals, since the trypomastigotes and epimastigotes forms come from the first and for that reasons its response to medicaments has less importance. The only drugs which are used in human Chd due to ethical and efficiency reasons are nifurtimox (NF) and benznidazole (BNZ). Other useful medicaments, but with no generalize application are: allopurinol and itraconazole. NF acts by the production of free radicals: superoxide anions, hydrogen peroxide and electrophilic metabolites. BNZ inhibits the biosynthesis of macromolecules. To day there is consensus that Chd must be treated in all its periods: Acute, latent or indeterminate chronic and determinate chronic: cardiopathy and digestive megasyndroms. This concept is based in the presence of DNA of T.cruzi by PCR in chronic cases were the microscopy don’t find their.  The treatment is able to modify the natural evolution of the disease and due to the great amount of chagasics patients the therapy helps to resolve a Public Health problem. The only cases which have no indications for treatment are chronic chagasic cardiopaths with terminal heart insufficiency and “Core bovis”. NF is prescribed at dose of 8mg/kg/day in adults during 30-60 days, and 10mg/kg/day in children during the same period. BNZ is given at dose of 5mg/kg/day during 60 day in adults and 5-10mg/kg/day (average 7.5 mg) during the same period in children. Due to the secondary effects of the drugs: generalized, digestive of the skin and of CNS, the patients must be controlled clinically and by laboratory tests: hemogram, hepatic profile, before, during and after the therapy.  More or less 30% of the patients present secondary effects.  New born, suckling and small children tolerate better the drugs. The acute cases: acquired and congenital, chronic indeterminate and determinate initial and intermediate cases must receive treatment.