Abstract
The effects of the following drugs on urinary coproporphyrin estimations were studied: fouadin, tartar emetic, coramine, emetine hydrochloride, carbon tetrachloride, hexylresorcinol, and atebrin. None of these substances interferes directly with the fluorimetric determination of urinary porphyrin if porphyrin is extracted from urine by ether or ethyl acetate and subsequently re-extracted into the aqueous phase with hydrochloric acid. Persons under treatment with tartar emetic showed a significantly higher coproporphyrin excretion. For this reason the coproporphyrin test for abnormal lead absorption is likely to be unreliable in persons treated with tartar emetic.