Bo He (Field Mint)

Name

Bo He (field mint, Mentha haplocalyx, Herba Menthae), recorded in the Xinxiu Bencao. This is the Chinese medicinal mint, not the same plant as every grocery peppermint tea — though the family is the same.

Source and quality

Plant

The aerial parts of the perennial Mentha haplocalyx Briq., family Lamiaceae.

Where it is grown

Mainly Jiangsu, Zhejiang and Hunan.

Harvest

Summer and autumn, on a dry day, when stems and leaves are full or after the third flowering.

Smell and taste

A clean, penetrating aroma; acrid and cooling after you crush a leaf.

Better grade

Plenty of deep-green leaf, strong smell, a fresh cooling taste.

Processing

Cut into sections; used unprocessed.

Nature and action

Acrid, cool; enters lung and liver. Disperses wind-heat; clears the head and eyes; eases sore throat; helps a rash surface; expels wind and eases itching.

When it is used

Wind-heat exterior pattern, or warm disease at the defense aspect

Bo He disperses surface pathogens and can encourage a light sweat. It is a standard herb for a wind-heat cold and for the early, defense-aspect stage of a warm disease, often with other wind-heat or heat-toxin herbs — Yin Qiao San is the usual example. It can also sit in a wind-cold formula as a small, cooling assistant.

Headache, red sore eyes, sore throat, itching

It clears the head and throat and can ease wind-type itch. For wind-heat rising to the head: Man Jing Zi, Chuan Xiong, Bai Zhi. For liver-heat red, watery eyes: Ju Hua, Mu Zei, Shi Jue Ming. For a swollen sore throat: Jie Geng, Niu Bang Zi, Jiang Can. For itchy wind rash: Jing Jie, Fang Feng, Jiang Can.

Early measles when the rash is stuck

When wind-heat on the exterior and heat in the interior keep a measles rash from coming out evenly, Bo He is used with Chan Tui and Niu Bang Zi to help the rash surface. That is a classical pediatric indication, not a reason to treat measles at home.

It also soothes liver qi and can move damp in the middle, so it appears for rib-side distension, stomach fullness, and summer-damp vomit or diarrhea.

Dose

Decoction 3–10 g, added near the end of cooking so the aroma is not boiled off. The leaf (Bo He Ye) is stronger at sweating and releasing the exterior; the stem (Bo He Geng) is used more to move qi and settle the middle.