What is Stool wood (onyame dua)?

Stool wood is the bitter bark of a tall forest tree, Alstonia boonei. In West African home medicine it was boiled into a drink for fever, malaria and body pain. The Akan name onyame dua means "God's tree"; the Yoruba name is ahun.

The tree grows across Ghana, Nigeria, Cameroon and nearby countries. Its soft white wood was carved into stools, drums and coffins, which is where the English name comes from. Healers used the bark, and sometimes the leaves and the milky sap.

The honest verdict on evidence: there is almost none in people. Nearly all of the research sits in test tubes and in rats and mice. Long and respected use in a tradition is not proof that a plant works, and it is not proof that it is safe.

How does Stool wood (onyame dua) work?

No one has shown how stool wood acts in the human body. The ideas below come from lab and animal work only.

In test-tube studies, bark extracts slow the growth of the malaria parasite. The effect is much weaker than that of standard malaria drugs. Whether it clears malaria in a person has never been shown.

In rats and mice, bark extracts reduced swelling and pain in lab models. Some of this is linked to two plant compounds, lupeol and ursolic acid. These are animal findings, not proof of benefit in people.

Echitamine, the main alkaloid in the bark, lowered blood pressure in animal tests. It also slowed the heartbeat. That same action may explain the dizziness some users describe.

Animal work also points to a cost. In rodents fed higher doses for weeks, blood markers for the liver and kidneys shifted. This is one reason the plant is treated with care rather than as a gentle tonic.

What forms does Stool wood (onyame dua) come in?

The usual traditional form is a decoction: bark chips simmered in water to make a very bitter drink.

Other forms seen in markets and shops: - Dried bark chips or shavings, sold loose - Powdered bark, sometimes in capsules - Alcohol tinctures and bitters - One plant among many in packaged herbal malaria or "blood" mixtures - Leaf poultices and sap applied to the skin in some areas

Packaged mixtures are a particular problem. The label may not say how much stool wood is in them. Some products sold for malaria have also been found to contain added pharmacy drugs.

Where it comes from:

Stool wood held high standing in West African practice, and the Akan name treated it as a sacred tree.

Healers in Ghana, Nigeria and Cameroon used bark decoctions for fever and malaria, aches and joint pain, and for coughs and chest tightness. Women were given it after childbirth to help clear the afterbirth and to encourage breast milk. Some traditions used it for worms, snakebite and skin sores.

The tree also carried social weight. Its wood was used for stools and for carved figures, and the tree itself was often left standing when forest was cleared.

The bark appears in African herbal pharmacopoeias and in national lists of medicinal plants. That records its traditional standing, not a verdict on whether it works.

What does Stool wood (onyame dua) help with?

• Fever and malaria: This was the main traditional use across the region. Bark decoctions were drunk at the first sign of fever. In test tubes, extracts slow the malaria parasite, and in infected mice they lower parasite counts. There are no good human trials of the bark alone. This matters more than usual. Untreated malaria can turn severe fast, especially in children and pregnant women. Fever needs a test and proper treatment, not a wait-and-see herbal drink.
• Joint pain, muscle pain and rheumatism: A long-standing use, taken as a drink or rubbed on as a poultice. In rats and mice, bark extracts reduced paw swelling and pain responses. Lupeol and ursolic acid are the likely drivers. No human trial has tested it for arthritis or back pain. Whether the animal effect carries over to a person is unknown.
• Afterbirth care and breast milk supply: Birth attendants gave the bark drink to help the womb clear after delivery and to boost milk. The womb-tightening action is part of why the plant is unsafe in pregnancy. Animal work supports an effect on uterine muscle. There is no human evidence that it increases milk. The alkaloids may pass into breast milk, and that has not been studied. This use is best avoided.
• Asthma and chesty coughs: Bark and leaf preparations were used for wheeze and tight chest. Some animal and cell work suggests a relaxing effect on airway muscle. This is early laboratory work. No human trial supports it. Asthma can be fatal when undertreated, so an inhaler is not something to replace.
• Intestinal worms: Bitter bark drinks were a common traditional worm remedy. Extracts have killed worms in test-tube studies. That is a long way from clearing worms in a person. Modern worm medicines are cheap, single-dose and well tested. There is no human evidence placing this bark near them.
• Skin sores and snakebite (applied to the skin): The milky sap and bark pastes were applied to sores, boils and bites. Lab tests show some activity against bacteria. Whether that happens on human skin is not established. Snakebite needs emergency care and antivenom. Nothing applied to the skin treats it.

What are the side effects of Stool wood (onyame dua)?

• Nausea and vomiting
• Stomach pain and diarrhoea
• Dizziness or light-headedness
• A drop in blood pressure
• A slower heartbeat
• Headache
• Cramping of the womb, with bleeding or miscarriage risk in pregnancy
• Signs of liver strain, such as yellow eyes or dark urine (rare, reported at high intake)
• Skin rash from the sap

Good to know:

Most reports are of stomach upset and dizziness, and these settle when people stop.

The serious concerns are less common but real. They are the blood pressure and heart rate effects seen in animals, the womb-tightening action, and the liver and kidney changes seen in rodents given the bark for weeks.

There is no safety monitoring system for this plant. That means mild effects are probably underreported and rare serious ones may never be counted.

How much Stool wood (onyame dua) should you take?

• Recommended daily: This page gives no amount, and that is a deliberate choice. There is no agreed safe dose for stool wood bark. No regulator has set one, and no human trial has tested one. The alkaloid strength of the bark swings widely between batches, so the same spoonful can be mild one time and strong the next. The alkaloids also act on blood pressure and heart rate in animal tests. With a plant like that, a rough home measure is not a small risk. If you are considering it, talk to a doctor or pharmacist first, and bring the actual product with you.
• Best time of day: Time of day has not been studied and does not matter here. The open questions are dose and safety, not timing.
• With or without food: No evidence points either way. The bark is very bitter and often upsets an empty stomach. Nausea and stomach pain are the most common complaints reported.
• Time to effect: There is no reliable human data on how fast it acts, or whether it acts at all. Traditional users expected a bitter fever drink to work within days. It may do nothing for your complaint, and a delay in real treatment for malaria or asthma can be dangerous.
• How long to take it: No safe length of use can be given. Rodents fed the bark for several weeks showed changes in liver and kidney blood markers, so repeated daily use is the pattern of most concern. Traditional use was short and for a specific complaint, not ongoing.