Peppermint Oil

In Roman mythology, a jealous Persephone crushed the nymph Mentha to dust and Pluto changed her into the peppermint plant.

Latin name: Mentha piperita
*Peppermint is a hybrid of two other plant species; spearmint (Mentha spicata) and watermint (Mentha aquatica)

Peppermint can usually be found in warm, moist climates, near bogs or on the banks of a stream. It is said that it is best that “harvesting should be carried out on a dry, sunny day, in the late morning, when all traces of dew have disappeared”.

A precaution I found at Herbal Picnic:
PRECAUTIONS:
Do not ingest pure peppermint oil or pure menthol, as both are very toxic & in the case of menthol, can be fatal.
Those who should avoid using peppermint include women with a history of miscarriage & anyone with gallbladder or bile-duct inflammation, obstruction, or a related condition.
Daily use of peppermint can overly relax the peristaltic actions of the colon & because of this is not recommended after dinner.