Ето цитат от kellymom.com
Peppermint tea is a very weak form of peppermint and only large amounts (quarts) would be expected to decrease milk supply
Other herbs that can decrease milk supply: Peppermint (Mentha piperita), Spearmint, Parsley (Petroselinum crispum), Chickweed, Black Walnut, stinging nettles (not nettle - that increases milk supply), Yarrow, Herb Robert (Geranium robertianum), Lemon Balm, Oregano, Periwinkle Herb (Vinca minor), Sorrel (Rumex acetosa).
Sage, peppermint, spearmint, lemon balm, oregano, and cabbage leaves can all be incorporated into a pressed oil (cold pressed or hot) to make massage oils for milk suppression.
Peppermint essential oil has been used traditionally for decreasing milk supply. Peppermint tea is a very weak form of peppermint and only large amounts (quarts) would be expected to decrease milk supply. Some women have successfully used the strong peppermint candies (for example, Altoids® Curiously Strong Peppermints) for decreasing milk supply (a few per day aren't likely to affect supply, though).
Ще рече: чаят от мента е много слаб извлек от мента и само от големи количества от него (кварти...не знам в литри какво е) може да се очаква да намалят количеството мляко.