Shao Yao Gan Cao Tang

Shao Yao Gan Cao Tang (Peony and Licorice Decoction), from the Shang Han Lun (Discussion of Cold-Induced Disorders) by Zhang Zhong-Jing.

Actions: Tonifies yin and blood; Replenishes body fluids.

Presentation: Spasms and cramps due to yin, blood and body fluid deficiencies: smooth or skeletal muscle spasms and cramps in various parts of the body, and tightness of the tendons and ligaments.

Cautions:

• Use with caution in hypertension: the high dose of Gan Cao may cause water retention
• Avoid cold or raw, pungent or spicy, and oily or greasy foods while taking it

Toxicology: In mice, the combined formula produced fewer side effects than the individual herbs.

Herb–drug interactions:

• Neuroleptic-induced hyperprolactinemia: 11 schizophrenic patients, 4 weeks; prolactin fell from 28.9 to 22.0 ng/mL without potassium change, adverse reactions or psychotic exacerbation
• Paclitaxel-induced myalgia/arthralgia decreased with L-glutamine and this formula
• GnRH agonist-induced menopausal symptoms relieved without significant change in serum estradiol

Pharmacological effects reported:

• Smooth muscle: marked inhibition of intestinal smooth muscle in rabbits
• Skeletal muscle: marked relaxation, partly attributed to lowered membrane calcium and potassium permeability
• Analgesic: very effective in animals but only slightly in humans, where effect increased significantly when combined with acupuncture

Source: Chen JK, Chen TT. Chinese Herbal Formulas and Applications: Pharmacological Effects & Clinical Research. Art of Medicine Press, 2009, p. 599.

Cook both herbs in 3 cups (600 mL) of water down to 1.5 cups (300 mL); take warm and strained in two equal doses.