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Traditional Chinese medicine

PoriaWolfiporia cocos (syn. Poria cocos)

Poria (fu ling) is a fungus in five classic Chinese digestive formulas; 14 trials of Shen Ling Bai Zhu San in chronic diarrhea (1,158 adults) found higher satisfaction.

Botanical name
Wolfiporia cocos (syn. Poria cocos)
Part used
sclerotium (the dense underground fungal mass), dried and sliced
Also called
pinyin Fu ling (茯苓); Hoelen, Poria cocos, Bukuryo (Japanese), Poria sclerotium
Used in
Traditional Chinese medicine
Taken for
Loose stools and diarrhea, Bloating, Appetite
Sold as
decoction, granule extract, powder, capsules, dried slices

The plant

Poria, or fu ling, is the dried sclerotium of the wood-rotting fungus Wolfiporia cocos. A sclerotium is a hard, dense storage mass that the fungus forms underground, and for medicine it is cut into slices or cubes and dried. The Chinese materia medica has used it for more than two thousand years, and a Wolfiporia review describes it as a dual-purpose medicine and food resource in China, Korea, Japan and North America.

The drug has several parts that the tradition keeps apart: the white inner mass (bai fu ling), the red outer layer (chi fu ling), the skin (fu ling pi) and the piece grown around a pine root (fu shen). Most digestive formulas call for the white mass. It goes into a water decoction, a powder, a granule extract or a capsule, and it is a named component of Si Jun Zi Tang, Liu Jun Zi Tang, Shen Ling Bai Zhu San, Xiao Yao San and Huo Xiang Zheng Qi San.

How the traditions use it

Traditional Chinese medicine (about TCM)

The materia medica gives fu ling as sweet, bland and neutral in temperature, and credits it with draining dampness, strengthening the spleen and calming the heart and spirit. In the tradition’s vocabulary dampness is a heavy, fluid-like influence that shows up as loose stools, a bloated abdomen, a sense of fullness and poor appetite, and fu ling is the herb the texts reach for when spleen weakness and dampness occur together. That is why it sits next to bai zhu (atractylodes) in so many formulas: the spleen is described as the organ that transforms food, and the two herbs are paired to support and to drain. That is how the texts frame it, and it is not a measured mechanism.

What is in it

A review in the American Journal of Chinese Medicine counted 166 chemical components in Wolfiporia cocos, mostly triterpenes and polysaccharides, along with sterols and diterpenes. In cell and animal studies these have been reported to have anti-inflammatory, antioxidant and antibacterial activity, and the review ties the mechanisms to the structures of the polysaccharides and triterpenes. These are laboratory findings. We could not find a human trial that tested a single poria compound for a digestive outcome.

What the human trials show

We could not find a controlled trial of poria on its own for a digestive outcome. The human data are trials of formulas that include it, and none of them can tell the fungus from the other herbs.

Shen Ling Bai Zhu San, which has fu ling in its name, was assessed in a meta-analysis of 14 trials with 1,158 adults who had chronic diarrhea. The formula, with or without conventional medicine, gave higher patient-reported satisfaction than conventional medicine alone and did not raise adverse events, though the authors asked for better-powered trials with objective outcomes. A separate analysis of 14 studies with 1,335 participants who had chronic gastritis found a relative risk of 1.29 (95% CI 1.21 to 1.37) for the formula over conventional therapy, with the authors rating the quality of evidence as not high. For modified Si Jun Zi Tang (ginseng, white atractylodes, poria and licorice), a meta-analysis of 32 studies with 2,780 patients who had chronic atrophic gastritis found clinical efficacy at RR 1.241 (1.199 to 1.285).

In functional dyspepsia, Liu Jun Zi Tang (rikkunshito) is the poria-containing formula with the most trial data. A 247-person placebo-controlled trial found 33.6 percent responders on rikkunshito and 23.8 percent on placebo, which was not statistically significant (p = 0.09). A 52-trial meta-analysis found a relative risk of 1.21 (1.17 to 1.25) against Western drugs; those trials compared rikkunshito with Western drugs and were not placebo-controlled. A separate analysis of 24 studies with 2,175 participants found no significant difference on the Gastrointestinal Symptom Rating Scale (SMD -0.07, 95% CI -0.31 to 0.17), though a 5-point symptom scale favored rikkunshito, and most of those studies had high or unclear risk of bias.

Not tested: poria alone, and its polysaccharides, for any digestive symptom.

StudyDoseWhat it found
Meta-analysis of 14 RCTs, 1,158 adults with chronic diarrhea (Shen Ling Bai Zhu San) PMID 35635135Formula, with or without conventional medicine; doses variedHigher patient satisfaction than conventional medicine alone; no increase in adverse events
Meta-analysis of 14 studies, 1,335 people with chronic gastritis (Shen Ling Bai Zhu San) PMID 36156925Formula; doses varied by trialRR 1.29 (95% CI 1.21 to 1.37) vs conventional therapy; recurrence RR 0.24; evidence quality not high
Multicenter placebo-controlled RCT, 247 people with functional dyspepsia (rikkunshito) PMID 247662952.5 g three times a day for 8 weeksResponders 33.6% vs 23.8% on placebo, p = 0.09 (not significant); epigastric pain improved, p = 0.04
Meta-analysis of 32 studies, 2,780 patients with chronic atrophic gastritis (modified Si Jun Zi Tang) PMID 38669406Modified formula; doses variedClinical efficacy RR 1.241 (1.199 to 1.285) vs Western drugs

How much the studies and the texts used

No trial gives a dose of poria alone. The formula trials used it inside a mixture: the 247-person rikkunshito trial gave 2.5 g of the extract three times a day for 8 weeks, and a Belgian crossover trial gave the same 2.5 g three times a day for 4 weeks. The traditional preparation is a water decoction of the sliced white mass, simmered with the other herbs of the formula and drunk in divided doses; the gram weight in a decoction differs from formula to formula. Granule extracts, pills and capsules of the named formulas are sold in ready-made form.

Doses here describe what studies and pharmacopoeias used. They are not a recommendation for any person; a clinician or pharmacist who knows your medicines and conditions is the right person to ask.

Side effects and cautions

In the trials we read, formulas with poria were generally well tolerated: the Shen Ling Bai Zhu San review found no increase in adverse events over conventional medicine, the rikkunshito placebo trial reported no severe adverse events, and a Belgian crossover trial of rikkunshito recorded no adverse reactions in 23 completers. The chronic gastritis review concluded that the safety of Shen Ling Bai Zhu San remains unclear. Poria itself has no pregnancy or breastfeeding data in what we read. On product quality, a survey of Asian traditional remedies bought in the USA, Vietnam and China reported arsenic, lead and mercury levels it classed as toxic in 49 percent and above public-health guidelines in 74 percent when used as directed; the abstract does not say that poria products were among those sampled.

Interactions

Neither the reviews nor the trials we read report an interaction between poria and a medicine, and we found no study built to look for one. The tradition describes fu ling as promoting urination, which is a classification and not a measured diuretic effect. The formulas that contain it also hold ginseng, licorice and ginger, so a granule or patent formula takes on the interaction notes of those herbs.

Poria on the shelf: the products that contain it

The products here name poria among their actives. How much of it a serving holds, and whether that matches any trial, is on each page.

Snap Dynasty Stomach Chi 4.5 out of 5 from 162 ratings from Amazon · $1.50 per day at two capsules three times a day ($29.99 for 120 on the brand site, $29.98 on Amazon, a 20-day bottle); the 60-capsule bottle is $17.99

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Often paired or compared

TCM Atractylodes Atractylodes macrocephala (bai zhu); A. lancea (cang zhu) TCM Ginseng Panax ginseng TCM Pinellia Pinellia ternata TCM Coix Coix lacryma-jobi var. ma-yuen TCM Chinese yam Dioscorea oppositifolia (also written Dioscorea opposita)

The questions that come up

Is poria a mushroom?

It is a fungus, but the part used is not a mushroom cap. It is the sclerotium, a dense underground mass formed by Wolfiporia cocos, which is dried and sliced before use.

What does fu ling do in the classic formulas?

The texts pair it with bai zhu (atractylodes) in Si Jun Zi Tang, Shen Ling Bai Zhu San and others. They describe it as draining dampness while the other herb supports the spleen. That is the tradition’s explanation, not a measured mechanism.

Does poria work for chronic diarrhea?

A meta-analysis of 14 trials of Shen Ling Bai Zhu San in 1,158 adults found higher patient satisfaction than conventional medicine alone. The formula has many herbs, so the result cannot be credited to poria alone.

Has poria been tested alone?

We could not find a controlled trial of poria on its own for a digestive symptom. Its laboratory research is on polysaccharides and triterpenes in cells and animals.

Is poria the same as the Poria in some mushroom blends?

Some supplements sell a fungal extract or powder. That is a different preparation from the sliced sclerotium simmered in the formulas used in the trials.

Sources