What is Button weed (craw-craw herb)?

Button weed is a small weedy plant from West Africa. Its leaves are used on the skin for itchy, crusted rashes. The best known use is for "craw-craw", a scabby, very itchy skin complaint.

Botanists call the plant Mitracarpus scaber. In Hausa it is known as goga masu. It grows as a common roadside and farm weed across the savanna belt.

Here is the honest verdict on the evidence. In lab dishes, extracts of the leaf slow skin fungi and some bacteria. Good human trials are few, small and old.

So the real-world benefit for your skin is not proven. Long and steady use in tradition is not proof that a plant works. It is also not proof that a plant is safe.

How does Button weed (craw-craw herb) work?

The proposed action is simple: the leaf is thought to kill or slow the germs that live in the top layer of skin.

Most of this work was done in test tubes, not on people. In laboratory tests, leaf extracts slowed ringworm-type fungi, also called dermatophytes. They also slowed some skin bacteria, including staph species.

A compound called harman has been pulled from the leaf and tested on its own. In those lab tests it was active against skin fungi. Whether enough of it reaches living skin to help is not established.

Tannins in the plant bind protein and may dry a weeping sore. That effect is seen in the test tube and in general plant chemistry. It has not been measured properly in people using this herb.

No clear mechanism is known for the older internal uses, such as toothache or stomach upset. Treat those claims as untested folklore rather than as pharmacology.

What forms does Button weed (craw-craw herb) come in?

Most forms are made for the skin, not for swallowing.

Common forms include:

- Fresh leaves crushed and rubbed on the skin - Dried leaf powder, often stirred into shea butter or palm oil - Medicated soaps and washes sold in West African markets - A leaf ointment developed by pharmacy researchers in Burkina Faso - Loose dried herb for a wash or poultice

Capsules and standard extracts are not a normal form for this plant. Products are rarely standardised, so strength is often unknown.

Where it comes from:

Button weed has a long and well recorded place in West African folk medicine. The Hausa name goga masu points to its use as a rub for the skin.

Healers in Nigeria, Burkina Faso, Ghana, Mali and Senegal applied the crushed leaf to craw-craw, ringworm and sores. It was also put on wounds, boils and eczema-type rashes.

Some communities used it for toothache, headache and stomach trouble. A few sources record use on the sores of leprosy.

In the late twentieth century, pharmacy researchers in Burkina Faso turned the leaf into a skin ointment. That work put the plant on record, but it did not settle whether it helps. This page describes that history; it does not advise you to treat yourself.

What does Button weed (craw-craw herb) help with?

• Craw-craw (an itchy, crusted skin complaint): This is the use the plant is named for. Healers rubbed the crushed leaf or leaf powder on the rash. The evidence is thin. Lab tests show activity against skin fungi and some bacteria. Controlled human trials for craw-craw are lacking. Craw-craw can be scabies, a fungal infection, or infected eczema. Each needs a different treatment. Guessing wrong wastes time and lets the rash spread.
• Ringworm and other fungal skin infections: This is the best supported use, and the support is still mostly from the lab. Leaf extracts slowed dermatophytes (ringworm fungi) in test-tube work. Harman from the leaf was active in the same setting. Small reports from Burkina Faso describe skin improving with a leaf ointment. These were early studies with few people and no strong comparison group. Proven antifungal creams from a pharmacy have far better evidence.
• Minor sores, boils and wounds: Tradition used the leaf as a dressing for sores and boils. Tannins in the plant can dry a weeping surface, which may be why it felt useful. That is chemistry, not a tested clinical effect. Raw plant material is not sterile. Putting it on a deep or dirty wound can add germs rather than remove them.
• Eczema-type itchy rashes: Traditional healers applied the leaf to many itchy rashes, not only infected ones. There is no human trial showing it helps eczema. Plant material on broken skin can also trigger an allergic rash. If a rash is dry, itchy and long-running, the cause is usually not an infection. In that case an antifungal plant would have no clear target.
• Traditional internal uses such as toothache and stomach upset: Some records describe chewing or drinking preparations of the plant. There is no reliable human evidence for any of these uses. Safety by mouth has not been properly studied. Because of that gap, this page gives no preparation and no amount for internal use.

What are the side effects of Button weed (craw-craw herb)?

• Stinging or burning where it is applied
• Redness and dryness of the treated skin
• Allergic contact rash, with itch, bumps or blisters
• Staining of skin, nails or clothing
• Worsening infection if raw plant material is put on an open wound
• Unknown effects when swallowed, since this has not been studied

Good to know:

Most reported problems are mild and local to the skin. Stinging, dryness and redness are the usual complaints.

Allergic rash is less common but does happen with plant preparations. Stop at once if a new rash, swelling or blistering appears.

Serious harm has not been well documented, but that partly reflects how little formal study exists. Absence of reports is not the same as proof of safety.

How much Button weed (craw-craw herb) should you take?

• Recommended daily: There is no agreed dose for this plant, and this page gives none for swallowing. Skin products that contain it carry their own label strength, usually a small percentage of leaf extract in a cream, soap or oil base. Those labels differ by maker and are rarely standardised. No dose is given for internal use because human safety by mouth has not been studied. Follow the label on any product you buy, and ask a pharmacist if the label is unclear.
• Best time of day: Time of day does not matter much for a skin application. Many people apply skin products after washing, when the skin is clean and dry. Evening use keeps a greasy base off clothes.
• With or without food: Food is not relevant, because the plant is used on the skin rather than swallowed. If you are offered an internal preparation, this page cannot advise on it. Speak to a doctor or pharmacist first.
• Time to effect: If a skin preparation helps at all, any change would usually take days to weeks. Fungal skin infections are slow to clear even with proven medicines. A plant preparation may work more slowly, or not at all. Itching that eases in minutes is often just the oil or butter base soothing dry skin.
• How long to take it: Traditional skin use was short: days to a few weeks, until the rash settled. A fixed safe length of use cannot be stated, because no trial has measured one. Skin infections that do not improve within about two weeks need a proper diagnosis. Long unbroken use on the skin raises the chance of an allergic rash.