Kampo Formulas: Extract Granules and Japanese Standardization

What a Kampo formula is

A Kampo formula is a fixed combination of several crude drugs. A 2026 review describes Kampo as based on fixed classical formulations and covered by national insurance, and calls its model highly standardized. [1] A 2011 review says Kampo still uses traditional prescriptions, while TCM also tends to create new drug combinations. [2] The overview is in Kampo medicine.

The same review says the thousands of Chinese crude drugs were reduced to about 300 in Japan, combined into about 300 prescriptions. [2] It also says the quantity of each drug in a Kampo formulation is much lower, in contrast with TCM. [2]

Published ingredients, as examples only

A 2020 review tabulates the ingredients of several formulas used in pain care. This is a description of what the table lists, not a recipe, and amounts are not given here.

Do not try to assemble or substitute ingredients from a list. Products and doses are set by regulators and prescribers.

From decoction to extract granules

Traditionally a formula is a decoction, a liquid made by cooking the crude drugs. The 2011 review says spray-dried granular extracts have increasingly replaced the traditional decoction, even though both are covered by national insurance. [2] Extract preparations make up to 95 percent of the Japanese Kampo market. [2] Doctors can still prescribe decoctions, selecting herbs from among 243 types covered by insurance. [4]

The review links the development of ready-to-use forms directly to the large increase in Kampo use. [2] A 2023 review adds that pharmacists in Japan also sell Kampo medicine as over-the-counter products. [5]

Standardization in Japan

The 2011 review says quality control of purity and toxicity is standardized in Japan, following the Japanese pharmacopoeia and international rules for Good Manufacturing Practice. [2] It adds that standardization of the main components has become possible and is a precondition of clinical research. [2]

A 2014 article on regulation explains the legal framework. Kampo medicines are the main traditional herbal medicines in Japan and are classified as pharmaceuticals. [6] Prescription ("ethical") Kampo formulations are prescribed under national health insurance, and over-the-counter formulations can be bought for self-medication. [6] Crude drugs and Kampo extracts are listed in the Japanese Pharmacopoeia, and the Approval Standards for OTC Kampo Products, which list 294 formulae, and the quality standards play a key role in regulation. [6]

Insurance covers three categories: formulation extracts, crude drugs including powders, and crude drug preparations. [7]

We could not read the pharmacopoeia monographs or ministry pages in this session, so we do not describe which marker compounds are tested for each extract or how tight the limits are.

Identity of ingredients matters

A 2025 historical study of rhubarb found that the original plant species behind this crude drug had been confused over its long history and across regions. [8] Ask a pharmacist about the identity and quality of any herbal product.

Licorice in many formulas

Licorice root is the most frequently used crude drug in Japan and is in 109 of 148 prescription Kampo extract formulas. [3] It can cause pseudoaldosteronism, linked to swelling, low potassium and high blood pressure, and the review says clinicians should monitor for it. [3] Tell your pharmacist about every herbal product you take. See licorice root tea.

Outside Japan

In the United States the FDA regulates dietary supplements under different rules than drugs, and can act against an adulterated or misbranded one after it reaches the market. [9] A 2026 report on one US distributor found its top five Kampo formulations differ from the most prescribed ones in Japan, and the authors cite regulatory status, practitioner education and product availability as possible reasons. [10] An imported or online product may therefore not match a Japanese prescription extract, even with the same name. Read adulteration and undeclared drugs and how traditional medicines are regulated by country.

Who should seek conventional care first

See a clinician for sudden, severe or worsening symptoms, and do not stop a prescribed medicine for any herbal product. Tell all your providers about what you take. [13]