Educational information, not medical advice — ask your doctor or midwife.
Keishi-ka-ryukotsu-borei-to (KRB) is a classical eight-herb Japanese Kampo formula with roots in the ancient Chinese medical text Shang Han Lun (c. 200 CE). The formula centers on cinnamon twig for warming circulation, paired with two mineral ingredients — dragon bone (a fossilized calcium carbonate mineral) and oyster shell — which together are said to anchor restless or scattered energy. It is one of the most researched Kampo formulas in modern Japanese clinical medicine.
The mineral components (dragon bone and oyster shell) are rich in calcium and are thought to calm overactive nerve signaling, supporting a quieter nervous system response to stress. Cinnamon twig improves peripheral circulation and body warmth, while white peony root and licorice work together to relax smooth muscle and ease tension. Ginger and jujube round out the formula to support digestion and buffer the formula's tolerability.
In Japan, KRB is most commonly prescribed as a standardized granule powder (notably Tsumura TJ-26) dispensed by licensed physicians under Japan's national health insurance system. Granules are dissolved in warm water and taken as a drink. In Chinese herbal practice, the formula is typically prepared as a decocted tea from raw herbs. Capsule and tablet forms are available in some Western markets but are less standardized.
The formula originates from Zhang Zhongjing's Shang Han Lun (Treatise on Cold Damage Disorders), written around 200 CE, making it nearly 1,800 years old. It was adopted into Japanese Kampo medicine during the Edo period and today is one of roughly 148 formulas covered by Japan's national health insurance, reflecting its mainstream clinical role in modern Japanese medicine.
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What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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