Gui Zhi, cinnamon twig.

What it is

Gui Zhi is the young twig of the cassia tree, Cinnamomum cassia. It comes from the same tree as Rou Gui, cinnamon bark, but the two are treated as separate herbs: the twig is lighter and moves outward, while the bark is described as warming more deeply. Neither is the same as the cinnamon in your kitchen cupboard.

How Chinese medicine describes it

In classical terms, Gui Zhi releases the exterior, warms the channels and supports Yang. It is also said to harmonise Ying and Wei.

Those two words are worth a moment. In Chinese medicine, Wei Qi is the protective layer that circulates near the surface of the body, in the skin and muscles. Ying Qi is the nourishing layer, closely linked with the blood and the inner organs. Much of classical herbal medicine is about keeping these in balance, and Gui Zhi is one of the main herbs used for that.

Where you’ll find it

• Gui Zhi Tang (Cinnamon Twig Decoction) is the first formula in the Shang Han Lun, the classical text at the centre of my herbal training. Gui Zhi is paired with Bai Shao, one warming and moving outward, the other gathering in.
• Gui Zhi Fu Ling Wan (Cinnamon Twig and Poria Pill), from the Jin Gui Yao Lue, is a classical formula often discussed in women’s health.

Because Gui Zhi is warming, the traditional texts advise care where there are signs of heat, and in pregnancy. That is part of what I look at before it goes into any formula.

How I use it

I never prescribe a single herb on its own. Gui Zhi would only ever be part of a formula written for one person, after a one-to-one consultation, and adjusted at follow-ups as things change. Before anything is made up, I check the formula against everything you take, prescribed and over the counter, and ask whether you might be pregnant.

Please don’t buy and take Chinese herbs on your own because of something you’ve read here. My guide to seeing a Chinese herbalist explains how consultations, sourcing and safety checks work.