Pyrrosia Leaf: Resolving Phlegm and Stopping Cough, Promoting Diuresis, Stopping Bleeding and Raising White Blood Cells

The Chinese herb shi wei (Pyrrosia leaf) is the whole plant of Pyrrosia lingua, Pyrrosia sheareri, Pyrrosia drakeana, Pyrrosia pekinensis, and Pyrrosia petiolosa of the Polypodiaceae family. It is also known as fei daojian, wugong qi, qixing jian, yizhi jian, jinxing cao, and shi lan. Folk people also call it "knife-edge medicine" (daokou yao); because Pyrrosia has a good hemostatic effect, folk medicine uses it to stop bleeding and heal wounds, hence the name.

The character "wei" in shi wei does not carry the grass radical; many people mistakenly write it as "wei" (reed). Pyrrosia is shaped like cowhide, hence the name. In classical Chinese, "wei" means leather; the "wei" in the idiom "weibian sanjue" (the leather straps binding the bamboo slips three times snapped) refers to the cowhide strips that linked bamboo slips together.

Pyrrosia has many folk uses. It both resolves phlegm and stops cough, treats urinary stones, and stops bleeding while raising white blood cells; cancer patients whose white blood cells drop after chemotherapy or radiotherapy may use Pyrrosia to raise them. These actions are widely used in folk medicine. Pyrrosia is also a common herb in oncology departments. Although it has no direct antitumor effect, it has some efficacy against tumor-induced bleeding, anemia, and effusions.

Traditional TCM holds that Pyrrosia leaf is bitter and sweet in taste and cold in nature. It enters the lung, kidney, and bladder meridians. It promotes diuresis and relieves strangury, clears lung heat and resolves phlegm, and cools blood to stop bleeding. It is used mainly for strangury, edema, difficult urination, phlegm-heat cough and wheezing, hemoptysis, vomiting of blood, epistaxis, metrorrhagia, and traumatic bleeding.

Modern pharmacological studies confirm that Pyrrosia indeed has antitussive and expectorant effects, as well as antibacterial and antiviral actions. It inhibits to varying degrees Staphylococcus aureus, hemolytic streptococci, Bacillus anthracis, Corynebacterium diphtheriae, and Escherichia coli; it also acts against influenza A virus and Leptospira. Pyrrosia sheareri additionally acts against herpes simplex virus.

The most common use of Pyrrosia is for TCM strangury (lin zheng). TCM strangury is very broad in scope: acute and chronic nephritis, pyelonephritis, urethritis, prostatitis, urinary calculi, and some sexually transmitted diseases with difficult urination all fall under it. Strangury commonly presents with dribbling, difficult urination, frequency, dysuria, hematuria, urinary retention, urethral burning, and hesitancy. Pyrrosia treats all types of strangury, and Pyrrosia decoction clearly increases urine output.

For strangury, Pyrrosia may be used alone or combined with other herbs. It relieves edema caused by nephritis and pyelonephritis and treats urinary stones; in some stone patients, stones are passed in the urine after taking Pyrrosia decoction. Hematuria in most stone patients improves after Pyrrosia decoction, urine volume increases, and renal colic is relieved. Pyrrosia also has a good inhibitory effect on prostaglandin biosynthesis, so it is often used for prostate diseases.

For strangury, when used as a diuretic, Pyrrosia may be combined with plantain herb (Cheqiancao), plantain seed (Cheqianzi), talc (Huashi), Poria (Fuling), and Alisma (Zexie); when used as a combined hemostatic and diuretic, it may be combined with Gardenia (Zhizi), Imperata rhizome (Baimaogen), and thistles (Da/Xiao Ji); when used to stop bleeding and nourish blood, it may be combined with cattail pollen (Puhuang), Angelica (Danggui), Peony (Shaoyao), and Sanguisorba (Diyu).

Another common use of Pyrrosia is to stop cough and calm wheezing. TCM holds that Pyrrosia clears lung heat and discharges heat, so it can resolve phlegm, stop cough, and calm asthma. For chronic bronchitis and bronchial asthma, Pyrrosia alone may be decocted and mixed with an equal amount of rock sugar to make Pyrrosia syrup, taken at any time. For example, decoct 500g of Pyrrosia, then add 500g of rock sugar and simmer into a syrup. Clinical studies show that this method treated more than 500 patients with cough and wheezing, with a total effective rate of 98%. It works well even for severe cases with dyspnea, those with concurrent emphysema, and even those with bronchial infection. To enhance Pyrrosia's antitussive and anti-asthmatic effect, it may be combined with Houttuynia (Yuxingcao), Solidago (Yizhihuanghua), Stemona (Baibu), Aster (Ziwan), and coltsfoot flower (Kuandonghua).

Pyrrosia is also widely used for various bleeding conditions—nosebleed, hemoptysis, gastric bleeding, hematuria, vaginal bleeding in women, and even traumatic bleeding—all may be treated with Pyrrosia to stop bleeding. It may be used alone or combined with other hemostatic herbs such as Bletilla (Baiji), Agrimonia (Xianhecao), Brake fern (Fengweicao), and thistles (Da/Xiao Ji) to strengthen the hemostatic effect.