Greek and Roman pharmacopias included a heavily symbolic and highly effective substance: human milk. In early Greek sources, human milk, sometimes specifically from “a woman who has borne a male child,” is recommended almost exclusively in treating women. The Greek use was adapted from an Egyptian ritual calling for the “milk of one who has borne a male child” to be poured from an anthropomorphic vase of Isis nursing Horus; the Egyptian application was not, however, gender specific. Similar vases were found in Greece in Geometric/Orientalizing contexts. These factors, together with evidence for Isis worship in Greece, suggest Greek knowledge of Egyptian ritual. Human milk therapies also appear in medical works arising in the Roman context, where they are not gender specific. Owing to Etruscan influence, Roman society was less polarized sexually than Greek, and it was more accepting of the female body. The Etruscans’ and Romans’ rich tradition of depicting nursing mothers sharply contrasts with Greek chariness about the female breast. Thus, we see that medical ideas and practices, as they were transmitted cross-culturally, were affected variously by each cultureís concepts of sexual gender.