Objective To compare the differences in intake and excretion between Musca domestica and other three species from families Muscidae and Calliphoridae which may help explaining the significance of house fly in the transmission of pathogens. Methods The four adult species were supplied with two concentrations of sucrose via modified capillary feeder assay system. The two sucrose concentrations were applied to one adult male/each experiment and the elimination spots were counted. Using 0.25 mol/L sucrose + 0.25% bromophenol blue, one active non-starved male/cup was observed carefully for 1 h to record its behavior. As a growing medium used in bacterial transmission experiments, undiluted trypticase soy broth was used to feed 3-day-old females and males of Musca domestica following two different diets upon emergence and the frequency of elimination spots was estimated. Results The two Musca species have half the weight of the two Phormia species. Comparing the volume of intake per hour, house fly took as much as the other species, all of which were larger. House fly produced twice, or more, the number of elimination spots/h than the other three species. Feeding the flies a sugar liquid diet resulted in producing more fecal spots than regurgitation spots. The male house flies produced less elimination spots/h when fed with trypticase soy broth than with the two sucrose solutions. Conclusions House flies eliminated more than the other examined fly species and most of these elimination events were defecation which implicates the fecal route for pathogen transmission by this important vector.