” … The existence of several elaborate incantation series in Ashurbanapal’s library, prescribing a large number of formulas to be recited in connection with symbolical rites to get rid of the demons, furnishes the proof for the practical significance attached to incantations in both Babylonia and Assyria.
These series, Babylonian in origin, revert to Sumerian prototypes and represent compilations stretching over a long period, with additions intended to adapt them to conditions prevailing in Assyria.
The scribes of Ashurbanapal were not indulging in a purely academic exercise in copying the archives of Babylonian temples ; their purpose, as was also the aim of the king, was to make Nineveh the central religious authority as well as the political mistress by having in their control the accumulated experience of the past, in dealing with the religious needs and problems of their own age.
A feature which these incantation series  have in common is the recognition of a large number of demons, with special functions assigned in many cases to the one class or the other.
So, for example, there is a demon Labartu, represented as a horrible monster with swine sucking at her breasts,  who threatens the life of the mother at childbirth; a group known as Ashakku who cause varieties of wasting diseases, another demon Ti’u, whose special function was to cause diseases, manifesting themselves by headaches accompanied by fever, and so on through a long list. It will be apparent that there is no differentiation between the demon and the disease. The one is the synonym of the other, and accordingly in medical texts the demons are introduced as the designations of the diseases themselves.
The names given to the demons in many cases convey the “strength” or “size” ascribed to them, such as Utukku, Alu, Shedu, Gallu, or they embody a descriptive epithet like AkKkhazu, “seizer” (also the name of a form of jaundice); ‘Eabisu, the one lying-in-wait; Labasu, “overthrower”; Lilu and the feminine Lilitu, “night-spirit;” Etimmu, ghost or shade, suggesting an identification of some demons with the dead who return to plague the living, Namtar, “pestilence,” and more the like.
The descriptions given of them, cruel, horrible of aspect, blood-thirsty, flying through space, generally invisible though sometimes assuming human or animal shape or a mixture of the two, further illustrate the conceptions popularly held.”
Morris Jastrow, The Civilization of Babylonia and Assyria, 1915, pp. 241-3.