What is Kihito?

Kihito is a Japanese Kampo herbal formula. It is sold in Japan as an approved medicine, Tsumura 65. Its old name in English is Spleen-Restoring Decoction.

It is chosen for people who are worn out, worried and sleeping badly. Kampo doctors also use it for poor appetite, pale skin and anemia (low red blood cells). The classic picture is weak digestion plus an overworked mind.

Here is the evidence in one line. The formula has centuries of traditional use behind it. Good human trials are scarce, and traditional use is not proof that a remedy works.

One safety point belongs up front. Kihito contains licorice root (kanzo), and it contains Polygala root (onji). Both carry known risks, and the safety section below explains them.

How does Kihito work?

The honest answer is that no one has shown how Kihito works in the body.

Kampo explains it in its own language. The formula is said to build "qi" (vital energy) and "blood", and to settle the mind. These are traditional ideas, not measured body functions.

Modern research is mostly in cells and animals. In animal work, ginseng and Polygala (onji) extracts appear to act on stress and memory pathways. Whether that happens in people who take Kihito is not established.

One effect is well proven in people, and it is a side effect. Licorice blocks an enzyme in the kidney (a protein that drives a body reaction). That can push potassium down and blood pressure up over time.

What forms does Kihito come in?

In Japan the usual form is a dried extract granule in single-dose sachets. Tablets and capsules of the same extract are also made. Both are taken with warm water.

Traditional practice boils the raw herbs into a decoction (a strong tea). This is less common today outside specialist clinics.

Products sold outside Japan vary a lot in strength and in how much licorice they hold. Check the label for the licorice (kanzo or Glycyrrhiza) amount before you buy.

Where it comes from:

Kihito comes from a Chinese text, Jisheng Fang, written by Yan Yonghe in 1253. The original name is Guipi Tang. It was built for tiredness, poor appetite and a restless mind.

Later Chinese doctors added Bupleurum and Gardenia to make a related formula. In Japan that version is called Kamikihito.

Japanese Kampo took up the base formula as Kihito. It is now a ministry-approved prescription formula in Japan, numbered Tsumura 65. The same recipe is still used in Chinese and Korean practice.

What does Kihito help with?

• Trouble sleeping: This is the most common reason Kampo doctors pick Kihito. The target person lies awake worrying and wakes tired and hungry for nothing. Support here is traditional. We could not find a published human trial of Kihito for sleep.
• Worry and low mood with tiredness: Kampo uses Kihito when anxiety sits on top of exhaustion. Small Japanese clinical reports describe use in anxious, run-down patients. These are reports, not controlled trials, so the effect cannot be separated from placebo.
• Long-term tiredness: Traditional use is strong here, and it is the core of the formula's name. Ginseng and astragalus are the classic "qi-building" herbs in the mix. There is no trial evidence that Kihito raises energy in people.
• Poor appetite and weak digestion: Kampo treats appetite and mood as one picture, and Kihito targets both. This is a long-standing use across East Asian medicine. Human trial data is lacking, and the Polygala in the mix can itself upset the stomach.
• Anemia (low red blood cells) with a weak stomach: Kihito is classically given for "blood deficiency" with pale skin and dizziness. That old idea is not the same as measured anemia. If blood tests show anemia, find the cause with a doctor. Iron loss and bowel bleeding need real treatment, not a herbal formula.
• Palpitations (feeling your own heartbeat): Traditional texts list palpitations from worry and overwork. Take care with this one. Licorice can lower potassium, and low potassium can itself disturb heart rhythm. New or fast palpitations need a doctor, not a herb.
• Forgetfulness and poor focus: Polygala (onji) has a long record for memory in East Asian medicine. Animal and cell studies suggest effects on memory pathways. Whether Kihito helps human memory has not been shown.

Which foods are rich in Kihito?

1. Licorice sweets, licorice tea and some soy sauces: they add to the licorice already in this formula
2. Dried longan fruit: sold as a snack, and one of the herbs in Kihito

Practical Tips:

Kihito is a medicine, not a nutrient, so no food supplies it. Watch only for extra licorice.

What are the side effects of Kihito?

• Nausea and vomiting
• Burning or heavy feeling in the stomach
• Loose stools
• Rash, itching or hives
• Muscle weakness or cramps, a sign of low potassium
• Swelling of the legs, face or hands
• Rising blood pressure
• Sudden weight gain from held fluid
• Raised liver blood tests, sometimes with tiredness or nausea
• Yellow skin or eyes (jaundice), which is rare but serious

Good to know:

Most people who take Kihito have no trouble with it. Stomach upset is the everyday complaint, and Polygala (onji) is the usual cause.

The licorice problem is the one to respect. It is called pseudoaldosteronism (a licorice effect in which potassium falls, blood pressure rises and the body holds fluid). It builds up with dose and time.

Older people, women and people on water pills are more at risk. It is not common at normal doses, but it is well documented and can be serious.

How much Kihito should you take?

• Recommended daily: In Japan the usual adult dose is 7.5 g of extract granules a day. It is split into two or three doses. Your doctor may set a lower dose. That daily amount holds roughly 1 g of licorice root. Do not add other licorice products on top of it. No dose has been set for children by good trials. Only give it to a child if a doctor prescribes it.
• Best time of day: Take it before meals or between meals, as Kampo practice advises. Doses are usually spread across morning, midday and evening. If one dose keeps you awake, ask your prescriber to shift it earlier.
• With or without food: The standard way is on an empty stomach with warm water. If it makes you feel sick, take it with a little food instead. Nausea is the most common complaint with this formula.
• Time to effect: Sleep and appetite may shift within one to two weeks. Tiredness often takes longer. Nothing is promised, and some people notice no change at all.
• How long to take it: Kampo practice reviews the formula after two to four weeks. If nothing has changed by about four weeks, stop and think again. Longer use raises the risk from licorice. If you take it for more than a few weeks, ask your doctor for a potassium blood test. Ask for liver blood tests too if you feel sick or unusually tired.