Towards Elucidation of the Problems of Skin-compatibility Testing/An investigation of hand-cleansing products using a modified Duhring chamber test The irritant potential of commercially available liquid syndets was investigated in a repetitive Duhring chamber test using a modified test procedure. Instead of regularly testing over a period of five days, the test was conducted only as long as it took for the first signs of irritation to appear. Among those products tested, substantial differences were found with respect to irritation and possible application time, and, as a result, to skin compatibility. Some of them produced skin irritation with the same intensity and just as quickly as the control substance, sodium lauryl sulfate (0.5%). These differences are not observed in a simple 24-hour epicutaneous test. For this reason, the latter, as opposed to the repetitive Duhring chamber test, appears to be unsuitable for comparative skin compatibility studies of syndets. The skin compatibility of special hand cleaners containing solvents was also investigated in a modified Duhring chamber test. In addition to the modification introduced above for the liquid syndets, here the maximum cumulative application time was reduced from 48 to 30 h. In this manner different degrees of skin compatibility to various special hand cleaners can be ascertained and taken into account when developing new products.