Four similar-looking preparations containing 4% chlorhexidine ('Hibiscrub', Surgiscrub', 'Uniscrub', 'Macrocide') were compared in a single-blind, randomized study in a group of 73 volunteers. The volunteers washed their hands with each preparation ten times over 9 h, one preparation day-1 on each of four days over two weeks. The acceptability of the agents was assessed using visual analogue scales which were analysed by paired t-test. There were marked differences between the products. 'Uniscrub' smelled worse (P less than 0.003) and felt worse than the others (P less than 0.003). 'Hibiscrub' lathered well but 'Macrocide' was found easiest to rinse off. 'Hibiscrub' and 'Surgiscrub' were the least irritant and had the best visual appearance. Despite apparent similarities, these chlorhexidine formulations varied in acceptability to users.