Substances which clean the skin surface. This means that, strictly speaking, any soap, or soap-like substance used in washing, is a detergent. At the present day, however, the term is largely used for the synthetic detergents which are now used on such a large scale. These are prepared by the cracking and oxidation of high-petroleum waxes with sulphuric acid. The commoner ones in commercial preparations are aryl alkyl sulphate or sulphonate and secondary alkyl sulphate.
In view of their widespread use, such detergents appear to cause relatively little trouble with the skin, but more trouble has been reported with the so-called ‘biological’ detergents – named because they contain an ENZYME which destroys protein. As a result they are claimed to remove proteins (stains such as blood, chocolate, milk or gravy) which are relatively diﬃcult for ordinary detergents to remove. Unfortunately these ‘biological’ detergents may cause dermatitis. In addition, they have been reported to cause asthma in those using them, and even more so in workers manufacturing them.