Wound disinfectants of various kinds were tested on microwounds and on different tissues in animals and in man. The analysis was performed by vital microscopy, electron microscopy, and microangiography. It was found that disinfectants, regardless of type, damaged tissue and interfered with tissue function, thereby increasing the injury already existing in a damaged tissue and delaying wound healing. The significance of these findings for wound healing is discussed. The importance of using the lowest possible concentration of disinfectant, consistent with adequate antiseptic effects, and of a non-toxic vehicle, is emphasized. It should be possible to modify already existing disinfectants according to the requirements of the tissue and to take not only the bacteria but also the injured tissue into consideration when new disinfectants are designed, tested, and selected.