Effects of two oral iron preparations on results of the benzidine test for occult blood in stools.

Thirty healthy male volunteers were used in this double blind trial. Two kinds of iron preparation and a placebo tablet containing no iron salt were used. The subjects were given one three times a day after meals in courses of 21 tablets. Stools collected before and after administration of the tablets were subjected to a benzidine test (Thornton and Illingworth, 1955). The results showed that both iron preparations increased the number of positive results obtained by means of the benzidine test. The analyses failed to show any significant difference between the effects of the two preparations.