We report the results of a prospective study in which the effectiveness of 70% alcohol (A), mercurochrome (M), a solution of alcohol and mercurochrome (AM) and 1% chlorhexidine (C) as umbilical antiseptics was tested on 311 normal newborn infants. Similar results were obtained by using A, M, or AM; however, when C was used umbilical colonization was significantly reduced as compared to when the other three antiseptic agents were used. The umbilical cords that had been scrubbed with A, M or AM were detached by the 8th day after birth, whereas those treated with C took 14 days to fall off. The use of chlorhexidine resulted in a marked increase in pure cultures positive for Gram negative bacteria (Proteus spp. and Pseudomonas spp.) which was not the case with the other three antiseptics tested.