What is Ryokyojutsukanto?

Ryokyojutsukanto is a Japanese Kampo herbal formula. It is used for a cold, heavy, aching feeling in the lower back, hips and legs. It is one of the 148 Kampo formulas on Japan's MHLW list (the health ministry's list of formulas covered by national health insurance).

The formula has four herbs: bukuryo (poria, a fungus), kankyo (dried ginger), byakujutsu (atractylodes root) and kanzo (licorice root). In Kampo thinking it is chosen for people whose low back feels cold and damp, as if they were sitting in cold water. It is also used in Japan as a supportive formula for cold feet and for needing to pass urine often at night.

It has a long record of traditional use, but long use is not proof that a remedy works. That point applies to everything below, and we will not repeat it in each section. Modern human trials of this formula are essentially absent, so its evidence grade is insufficient.

How does Ryokyojutsukanto work?

No one has shown how this formula works in the body. The idea behind it comes from Kampo theory, not from lab proof.

In Kampo terms, dried ginger is said to warm, poria and atractylodes are said to move excess fluid, and licorice is said to tie the mix together. In plain words, the formula was built to warm and dry a back that feels cold and waterlogged.

Some single herbs in it have measurable effects in lab studies. Ginger compounds can affect blood flow and gut movement. Licorice affects how the body handles salt and potassium, which is the main reason this formula needs care.

What forms does Ryokyojutsukanto come in?

Dried granules or powder are the usual form. In Japan these are made to a fixed standard and dissolved in hot water.

Other forms you may meet:

Tablets or capsules of the dried extract. A traditional decoction, where the raw sliced herbs are simmered in water and the liquid is drunk. Loose cut-herb packs sold for home brewing.

Products differ a lot in strength. Check the label for how much licorice or glycyrrhizin each daily dose contains.

Where it comes from:

The formula comes from the Jingui Yaolue (Essential Prescriptions of the Golden Cabinet), a Chinese medical classic written around 200 CE and attributed to Zhang Zhongjing. There it is described for a cold, heavy, aching low back.

Japanese doctors took the formula into Kampo practice and kept it in steady use. Its older Japanese name is Jinchakuto, and it is also written out as Kanzo-kankyo-bukuryo-byakujutsu-to after its four herbs.

It is a modest, small formula rather than a famous one, but it has stayed in the Japanese pharmacopoeia and on the national insurance list.

What does Ryokyojutsukanto help with?

• Cold, heavy, aching lower back: This is the main traditional use and the one the classical text describes. Kampo practitioners pick it when the low back feels cold and heavy rather than hot or sharply inflamed, and feels better with a hot bath or a warm pack. We found no published human trials testing it for back pain.
• Cold, heavy hips and legs: Traditional use extends the same pattern down from the low back into the hips and legs. There is no trial evidence for this use. If your leg pain is new, one-sided, or comes with numbness or weakness, see a doctor rather than self-treating.
• Cold feet with a feeling of dampness: Kampo practice uses warming formulas for people who feel cold in the lower body. This use rests on tradition alone. Cold feet can also come from poor circulation, thyroid problems or nerve damage, so persistent cold feet deserve a check-up.
• Passing urine often at night: Some Japanese practitioners use this formula when night-time urination comes with a cold, heavy low back. No trial evidence supports it. Frequent night urination can point to prostate trouble, diabetes or heart problems, so get it looked at.
• Bed-wetting in children (traditional use only): Older Kampo texts mention this use. There is no modern trial evidence, and the licorice content makes unsupervised use in children a poor idea. Do not give this formula to a child unless a doctor advises it.

Which foods are rich in Ryokyojutsukanto?

1. Licorice sweets and licorice tea: they contain glycyrrhizin, the same compound as kanzo, and add to the dose
2. Dried ginger and fresh ginger: kitchen amounts are small, but they share the warming compounds in kankyo

Practical Tips:

Cut back on licorice sweets and licorice tea while you take this formula, since the doses add together.

What are the side effects of Ryokyojutsukanto?

• Swelling in the ankles, face or hands
• Rising blood pressure
• Muscle weakness or cramps
• Low potassium in the blood, which can upset the heart's rhythm
• Weight gain from held-on water
• Upset stomach or nausea
• Rash or itching from an allergy to one of the herbs

Good to know:

Most people who take it for a short time have no trouble. The real concern is the licorice, which can cause pseudoaldosteronism (a licorice reaction where the body holds on to salt and water and loses potassium).

That reaction can raise blood pressure, cause swelling, and drop potassium far enough to weaken muscles or upset the heartbeat. It is more likely with higher doses, longer use, older age, and when other licorice products are taken at the same time.

Stop the formula and speak to a doctor if you notice new swelling, unusual muscle weakness, or a rising blood pressure reading.

How much Ryokyojutsukanto should you take?

• Recommended daily: In Japan the standard granule dose for adults is about 7.5 g of the dried extract product per day, split into two or three doses. Doses for children are lower and are set by a doctor. Outside Japan, product strengths vary widely, so follow the label and a practitioner's advice. Because of the licorice, keep an eye on the total glycyrrhizin you take each day from all sources.
• Best time of day: Usually two or three times a day, spread out. Many people take it morning, midday and evening.
• With or without food: Japanese practice is to take Kampo granules before meals or between meals, with hot water. If it upsets your stomach, taking it with food is acceptable.
• Time to effect: Traditionally, a well-matched Kampo formula is expected to shift symptoms within days to a couple of weeks. There is no trial data to confirm any time frame.
• How long to take it: Kampo practitioners often review a warming formula after two to four weeks. If nothing has changed by then, the pattern was probably not matched and the formula should be stopped. Long runs raise the risk from licorice. If you take it for more than a few weeks, ask your doctor to check your blood pressure and your blood potassium level.