Educational information, not medical advice — ask your doctor or midwife.
Cnidium is a seed-based herbal product sold mainly for itchy skin and for "male performance" claims. Human evidence for either use is very thin.
The plant sold under this name is almost always Cnidium monnieri. It is a small white-flowered plant in the carrot family. Its dried fruit, often called a seed, is the part used, and Chinese herbalists know it as she chuang zi.
The name causes real confusion. Several other Cnidium species grow wild in Europe and are not the same plant. Many labels do not name the species at all, so you often cannot tell what is in the bottle.
Most of what is written about Cnidium comes from laboratory and animal work on one of its compounds, osthole. Long traditional use is not proof that a remedy works, and it is not proof that it is safe. Treat the claims on the label as unproven.
No one has shown in good human trials how Cnidium works, or that it works at all.
The compound studied most is osthole. In cell and animal studies it appears to calm inflammation and to relax smooth muscle. Some rodent work suggests it acts a little like a calcium channel blocker, a type of blood pressure drug.
In test tubes, Cnidium extracts slow some fungi, bacteria and parasites. Whether that happens on human skin has not been established.
For the sexual-performance claims, the research is rat work. In those animals osthole appears to raise nitric oxide signalling in erectile tissue. That is a long way from a proven effect in men.
Animal studies have also looked at bone density, allergy and blood sugar. None of this has been confirmed in people. A mechanism seen in a dish is a hint for researchers, not a result you can count on.
Cnidium is sold in a few forms. None of them has been tested well in people.
- Capsules or tablets of powdered seed or seed extract, often standardised to osthole. - Loose dried fruit, simmered into a tea or decoction by herbalists. - Liquid tinctures.
- Washes, sitz baths and fumigations made from the boiled seed, used on the skin or around the genitals in Chinese practice. - Creams, ointments and medicated oils, usually mixed with other herbs. - Multi-herb "male vitality" blends, where the amount of Cnidium is often not stated.
Blended products are the hardest to judge. If a label will not tell you the species and the amount, you cannot know what you are taking.
Cnidium monnieri fruit has a long record in Chinese herbal medicine. It appears in early materia medica texts, including the Shen Nong Ben Cao Jing, which dates to around the first to third century CE.
Herbalists classed it as warming and drying. It was applied outwardly far more often than it was swallowed. Classical uses included washes for itchy, weeping skin rashes, scabies and vaginal itch.
Taken by mouth, it was given in old texts for impotence and infertility, usually within a formula rather than alone. Chinese sources also warned against it where "damp heat" signs were present.
Other Cnidium species recorded in European floras were never major medicinal plants. Modern Western supplement use began in the 1990s, when osthole research reached English-language journals.
Stop using it and see a doctor if any of these happen:
- Your skin blisters, burns or turns dark after sun exposure. - A rash spreads or gets worse rather than better. - You get swelling of the lips, face or tongue, or any wheeze. Call emergency services for these. - You feel dizzy, faint or unusually drowsy. - You get yellow skin or eyes, dark urine, or pain in your upper right belly.
Also see a doctor if skin symptoms have not improved after about a week, or if erectile problems are new. New erection trouble can be an early warning sign of heart or blood vessel disease.
In the United States, Cnidium is sold as a dietary supplement and is not reviewed for effectiveness before sale. In the UK and the EU it is not an authorised medicine, and products are sold as supplements or by herbal practitioners. No regulator has approved it to treat any condition.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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