Runchang Wan for Blood-Dryness-Type Constipation

Runchang Wan (Intestine-Moistening Pill) comes from Li Dongyuan's Pi Wei Lun (Treatise on the Spleen and Stomach). The original text says it "treats constipation from diet and overexertion, or dryness and obstruction with complete loss of appetite, as well as wind-binding and blood constipation, both of which cause obstruction. It moistens dryness, harmonizes blood, and disperses wind, and naturally frees the flow."

Runchang Wan is composed of Dahuang (Rhei Radix et Rhizoma, peeled), Dangguiwei (Angelicae Sinensis Radix tips), and Qianghuo (Notopterygii Rhizoma et Radix), each 5 qian (15g); Taoren (Persicae Semen, soaked in soup, skin and tip removed) 1 liang (30g); and Maziren (Cannabis Semen, hulled to take the kernel) 1 liang 2 qian 5 fen (41.5g). Preparation: apart from the Taoren and Maziren, which are separately ground into a mash, pound and sift the rest into a fine powder, bind with refined honey into pills the size of a parasol-tree seed. Take 50 pills each time, on an empty stomach, washed down with plain water.

This formula disperses wind and activates blood, and moistens the intestines to free the stool. It treats the "wind-binding" and "blood constipation" Li Dongyuan describes—constipation accompanied by blood deficiency and intestinal dryness. Because of insufficient fluids, the stool becomes bound and obstructed, and the feces passed are usually unusually foul. This condition corresponds broadly to constipation and incomplete intestinal obstruction in modern medicine.

Patent-medicine manufacturers produce Runchang Wan, which patients can buy at physical or online pharmacies. But Runchang Wan is not a medicine for long-term use. Dahuang in Runchang Wang frees the stool when first used, but long-term use easily leads to habitual constipation; this is due to the biphasic action of certain Chinese herbs. Therefore Runchang Wan is not suitable for treating habitual constipation.