Biocides are substances and products which, by other means than by mere physical or mechanical action, destroy, deter, render harmless, prevent the effect, or otherwise combat harmful organisms (bacteria, fungi, algae and microorganisms). This also includes products which are used for the control of insects, mice, rats and other pests, the effect of which is based on a chemical basis. In Germany, there are currently more than 30,000 biocidal products. Closely related to the term biocide is disinfection, i.e. free-market disinfectants are generally also biocidal products.