The Herb Cabinet 本草

薄荷 bò he

Mentha haplocalyx · field mint

Cool Pungent · Aromatic LungLiver

“A pinch of coolness added at the last minute, lid off, fire out. Mint is the breath of fresh air a stuffy formula — or a stuffy head — is waiting for.” — Lao Xinglin

What the tradition says

Bo he is the pharmacy's open window. Light, aromatic, and cool, it disperses wind-heat — the scratchy throat, headache, and feverishness of a heat-type cold's first day — and clears the head and eyes^[1]. Its subtler job appears in Xiao Yao San: a small, late-added pinch helps stuck liver qi vent, the way cracking a lid keeps a pot from rattling^[1]. Always added at the end of the boil; its medicine lives in the volatile oils that long cooking destroys.

What the research says

Western research concentrates on its close cousin peppermint, where the evidence is actually respectable: enteric-coated peppermint oil improves IBS symptoms in adults per multiple trials, and topical oil shows limited but suggestive results for tension headache^[2]. Field mint (Mentha haplocalyx) itself rides on the genus's pharmacology — menthol and friends — with little direct trial work.

Where to be careful

• Concentrated mint oil is a different animal from mint leaf tea: the

oil can cause heartburn and should never be applied to the faces of infants or small children (menthol inhalation risk)^[2].

• The tradition keeps this disperser away from the already-depleted and

sweating — you don't open windows in a house losing heat^[1].

In the pharmacy

Dried leaf and stem of Mentha haplocalyx, unmistakable to the nose. Add in the final minutes of a decoction, lid on briefly, then pour.

Reviewed 2026-08-25