Semmelweis' sesquicentennial: a little-noted anniversary of handwashing.

This review describes Semmelweis' achievement 150 years ago. User acceptability of hand disinfectants has been improved, but Semmelweis' observation that handwashing, in contrast to hygienic hand disinfection, is not always sufficiently effective, is not yet generally acknowledged, and the compliance of medical personnel to the rules of hand hygiene still remains an educational problem to be solved.