Excerpt
Except for pennyroyal (
Mentha pulegium), the members of the genus
Mentha, if distinguished at all in the folk literature, have borne their vernacular names interchangeably and have been used medicinally for such a broadly similar range of ailments that it is appropriate to discuss them together. Most records probably relate to the native water mint (
M. aquatica), the common species of wet places. That is widely known also as 'water peppermint' or 'wild peppermint', names rarely relating to the true peppermint (
M. ×piperita), which is a garden hybrid, originating in England in the seventeenth century. Though spearmint (
M. spicata) is probably always distinguished correctly, only two folk records of that have been found, while the solitary one for 'horse mint' cannot confidently be ascribed to any of the species or hybrids now recognized by taxonomists. Until grown as pot-herbs, some of which have crept out of gardens and become naturalised in the wild, 'mint' doubtless denoted a single wild entity for all practical purposes.
Like so many other members of the family Lamiaceae, mint has found its principal use in countering colds and coughs — though, curiously, the British records for that are all from the southern half of England: Dorset, Wiltshire, Warwichshire, Suffolk, and Norfolk. A secondary focus has been on the digestive system, as a cure for constipation, stomach-ache or inflammation of the appendix (Kent, Norfolk), perhaps also the 'stomach trouble' reported from Gloucestershire and even the 'heart complaints' for which 'horse mint' has been commended in Lincolnshire if those are 'heartburn' at least in part. But 'a pain in the side after jaundice', recorded from the Highlands, must belong in a separate category, as clearly does a tradition persisting in rural Somerset and the mining communities of Fife of relieving 'curdled milk' in nursing mothers by applying a hot 'peppermint' or spearmint compress to the breasts. The same applies to rubbing the gums with the leaves to ease the pain of toothache in Wiltshire.
Ireland's uses have been similar, but the two leading ones in Britain have exchanged their places there: indigestion and stomach pain have been the main troubles remedied (Cavan, Limerick, Cork and unlocalised records) whereas the only cold cure traced is a record from Co. Dublin — where it was eaten raw — and the only cough cure is represented by a spearmint syrup made with water-cress and honeysuckle for whooping cough in Cork. In the last county a decoction has also been drunk for headaches, while deafness has been treated there by squeezing the juice from nine plants and pouring a thimbleful into the relevant ear. Other Irish applications have been to jaundice in Limerick, measles in Cavan and nettle stings (as a counter-irritant) in Co. Dublin. In some unspecified part of the country a bunch tied to the wrist or worn elsewhere about the person has also been held to ward off infection.