methods for the treatment of physiological disorders , including protozoal infections in mammalian and avian species and gastrointestinal and cardiovascular disorders in mammalian species by administering a class of aralkyl - and aralkenyl - acyl , and thioacyl , guanidine compounds , pharmaceutical compositions containing such compounds for systemic administration , and a class of novel aralkenyl -, aryl - substituted cycloalkyl -, and arylsubstituted heterocycle - acyl and thioacyl guanidines .