Most molecules with hormonal or enzymatic action are found in living organisms, in contrast with synthetic chemicals used commonly as pesticides, cleaners and so forth. Being "natural" chemicals, it is widely assumed that hormones and enzymes are safe agents to use for biological control of weeds and animals pests, and also to accelerate beneficial processes, such as animal growth or decomposition of organic material. The manufacture and introduction of hormones into situations different from their usual environment carries potential risks. Their concentrated application at this time in ignorance of their long term effects could prove as disastrous as the overuse of synthetic chemicals.
In the early 1980's, enzymes were added to Australian washing powders to improve their cleaning action. They acted on stains derived from organic substances, such as fruit and oil, by breaking them down into simpler, non-staining, molecules. After a short while the products were withdrawn from the shelves and further manufacture forbidden. The enzymes were upsetting the operation of sewage plants, in particular the functioning of bacteria which decompose the organic wastes. Selective weedicides which have plant hormones as active agents were introduced in the 1970's and originally marketed as entirely safe. Increasingly stricter application and handling guidelines are being applied to their use.