Pork is a food taboo among Jews, Muslims, and some Christian denominations. Swine were prohibited in ancient Syria and Phoenicia, and the pig and its flesh represented a taboo observed, Strabo noted, at Comana in Pontus. A lost poem of Hermesianax, reported centuries later by the traveller Pausanias, reported an etiological myth of Attis destroyed by a supernatural boar to account for the fact that "in consequence of these events the Galatians who inhabit Pessinous do not touch pork". In Abrahamic religions, eating pig flesh is clearly forbidden by Jewish (kashrut), Islamic (halal) and Adventist dietary laws.

In some religions, an unclean animal is an animal whose consumption or handling is taboo. According to these religions, persons who handle such animals may need to ritually purify themselves to get rid of their uncleanliness.