The alleged ‘safety’ of malathion rests on rather precarious ground, although – as often happens – this was not discovered until the chemical had been in use for several years. Malathion is ‘safe’ only because the mammalian liver, an organ with extraordinary protective powers, renders it relatively harmless. The detoxification is accomplished by one of the enzymes of the liver. If, however, something destroys this enzyme or interferes with its action, the person exposed to malathion receives the full force of the poison.