Most of these rituals existed long before the germ theory of disease, and figure prominently from the earliest known religious systems of the Ancient Near East. Some writers remark that similarities between cleansing actions, engaged in by obsessive compulsive people, and those of religious purification rites point to an ultimate origin of the rituals in the personal grooming behaviour of the primates, but others connect the rituals to primitive taboos.
Some have seen benefits of these practices as a point of health and preventing infections especially in areas where humans come in close contact with each other. While these practices came before the idea of the germ theory was public in areas that use daily cleaning, the destruction of infectious agents seems to be dramatic. Others have described a 'dimension of purity' that is universal in religions that seeks to move us away from disgust.