She is not a demon in the ordinary Mesopotamian sense, and that is the first thing the texts insist on. Ordinary demons are dispatched — sent by an angry god, or by a curse, or by neglected obligations, and therefore removable by addressing whoever sent them. Lamashtu, Sumerian Dimme, is the daughter of Anu, expelled from heaven, and she acts on her own authority. Nobody sends her. Nobody can call her off. An exorcist facing her is not negotiating with a superior; he is fighting.
What she is described as doing
The incantation series named after her runs to three tablets and is unusually concrete about method. She comes to the house where a woman is in labour; she counts the months of the pregnancy; she touches the woman's belly; she seizes the infant seven times, takes it from the wet-nurse's lap, and drinks the blood of men and the milk meant for the child. She brings fever. She is called the one who slips in through the pivot-hole of the door, because a Mesopotamian door turns on a post in a socket and there is always a gap.
Her portrait on the amulet plaques is fixed and detailed: a lion's or bird's head with donkey's ears and teeth, naked, hairy, with long fingers and long nails and taloned feet, a snake gripped in each hand, and — the detail nothing else in the corpus prepares you for — a piglet suckling at one breast and a puppy at the other. She nurses animals while killing children. Whether that is meant as parody, as an inversion of the mother goddess, or as a statement that her nourishment goes to the wrong recipients, the plaques do not explain.
Shipping her downriver
The rituals against her are not spells so much as removals with a logistics plan. A figurine of Lamashtu is made and set up, and she is given provisions for a journey: bread, water, a comb, a spindle, a fibula or pin, sandals, sometimes jewellery — a travelling kit for a woman leaving a household properly. A black dog may be given her to carry the message. She is then placed on a small boat and sent off downstream to the underworld, or the figurine is buried at the city wall or under a threshold with its provisions.
The whole procedure treats her as a departing guest who must be seen out with the courtesies observed, and it is done that way for a practical reason: an insulted demon comes back. The plaques that show all of this — usually in stacked registers with the sickbed at the top, the exorcists in fish cloaks around it, and Lamashtu below on her donkey in her boat — are among the most information-dense objects ancient Mesopotamia produced. The finest, in the Louvre, has Pazuzu's head projecting above the top edge, looking down over the whole scene.
The medicine underneath
It would be a mistake to treat this as superstition standing in place of medicine, because the same practitioners were doing both. Assyrian and Babylonian medical texts prescribe plant preparations, bandaging, dietary measures and observation alongside the incantations, and a household could employ an asû, a physician working with materia medica, and an ašipu, an exorcist working with ritual, without any sense of contradiction.
What Lamashtu names is a real cluster of dangers: death in childbirth, puerperal fever, neonatal death, and the fevers of a hot floodplain. Attempts to identify her specifically with malaria are common and go beyond what can be shown — the symptom descriptions in the incantations are not a clinical record — but the underlying epidemiology needs no speculation. In a society where a substantial fraction of children died in their first year and a substantial fraction of women died delivering them, the most feared supernatural being was the one who did exactly that, and the response was an industry of amulets.
After Babylon
Child-killing female demons are one of the most persistent figures in Mediterranean and Near Eastern folklore, and Lamashtu is the earliest documented member of the family — followed by the Greek Gello and Lamia, by the demoness of the Aramaic incantation bowls, and by the figures named on Byzantine and later Jewish protective amulets, where the standard technique is to make the demon reveal her many names so that she can be bound by them. Whether these are descendants or independent solutions to the same terror is genuinely arguable, and the naming-the-demon device does look like a shared technology rather than a coincidence.
She is the Mesopotamian half of the comparison with Medusa, and she sits at the head of the monstrous feminine as the tradition's oldest example.
What readers ask
Does Lamashtu turn into Lilith?
No, and conflating them is one of the commonest errors in popular writing. The lilû and lilitu demons are a separate class of wind spirits with their own incantations, and the medieval Lilith is later still; her ancestry is set out on the Lilitu page. What is true is that Mesopotamian exorcists dealt with several distinct classes of being who threatened mothers and infants, that later traditions merged them, and that modern writing has merged them further.
Why is she a goddess rather than a demon?
Because her parentage is divine and the texts say so — she is Anu's daughter, and some incantations address her with respect before expelling her. The classification is deliberately awkward: she has the standing of a deity and none of the obligations. She receives no cult, grants no favours, answers no prayers, and cannot be bought. In a religion where the relationship between people and gods is essentially transactional — offerings for protection — a divine being outside the transaction system is genuinely terrifying, and that is what she is for.
Did anything actually work?
Against fever and infection, no. But the ritual has a function the medicine could not supply: it gives a household in the middle of an obstetric crisis something structured to do, a named adversary, and a procedure with an ending. The provisioning of the figurine and the launching of the boat are, whatever else they are, a way of closing an episode. Reading the plaques as failed pharmacology misses what they were for; reading them as evidence of what people feared most is exact.