Two possible Greek etymologies, one from στομαχος (‘stomach’) and the other from στομα (‘mouth’), make it difficult to infer the effect of this medicine.
s.
1pharm.med.medicinal preparation to cure disorders of the stomach or in the mouth:
(
MS: s.xv
) Stomacum (l. stoma[ti]cum??) ad cest (=medicinal preparation) a noun [...]. Aristole dist q’ele garist malades e defent les seins de maladies e si eist bon a palatinus
169.E597
[stomaticum] (s.xv)