The working of the curse depended in part on the correct procedure for making (see Creating the curse - materials and manufacture) and depositing the tablet (see Creating the curse - nailing and folding). It depended too on the use of appropriate formulae (see Creating the curse - Writing the curse), often repeated or reworked for additional power. Curse texts also sometimes drew on a ‘magical vocabulary’. This includes voces magicae, i.e. words without obvious meaning, charakteres i.e. symbols resembling letters, series of repeated vowels, the writing of the alphabet and names of deities and terms for divine attributes from the religions of the eastern Mediterranean. This ‘magical gibberish’ perhaps only served to lend the text a mysterious or arcane aura, but it was perhaps considered too that the gods and spirits understood this language.

Behind the magic of curses appears to lie the principle of ‘sympathy’. On this principle the characteristics of the tablet and the treatment to which it was subjected are also assumed to have been extended to the victims of the curse. The sympathetic connection could be established by identifying the victim (see Creating the curse - Writing the curse). It could be strengthened by associating the tablet with material linked to the victim, ‘stuff’ (ousia) such as hair or clothes (see Creating the curse - nailing and folding). The characteristics of lead (see Creating the curse - materials and manufacture), dull and blotchy, heavy and cold would serve to fatigue the victim. The reversal of letters, words and lines (see Curses and cursive - scripts) would confuse and disorientate, as would folding or rolling the text. Piercing (see Creating the curse - nailing and folding) of the tablet would assist in ‘fixing’ the victim. The cold and wet places (see see Creating the curse ­ plumbing the depths) in which tablets were frequently deposited would benumb them. Deposition in springs, graves or cellars would drag them downward towards the deities of the underworld. Together these different facets may have been thought to ‘fix’ or ‘bind’ the victim, but the degree of literal belief in the power of sympathy is unclear. Instead perhaps the curse presented the gods or spirits with an ‘analogy’ for the way in which they should put it into effect.

The practice of ‘magic’ and witchcraft was unacceptable in the Roman world (see Cursing in Greece and Rome), but it is not straightforward to distinguish ‘magic’ from ‘respectable’ religious practice. In Britain for example the practice of cursing also mostly took place alongside other ‘mainstream’ religious ritual in the province’s temples (see Creating the curse - plumbing the depths), rather than in polluted and dangerous places like cemeteries, the traditional haunts of the witch. In studying curse tablets we have an unusual opportunity to study the complexity of ancient magic and the difficulty of establishing clear-cut categories of magic and religion in a world in which there is no religious orthodoxy, populated by a myriad deities and cults.