What is King of the forest?

King of the forest is a shrub known to botanists as Senna alata. It grows across the Caribbean and much of the tropics. Its upright yellow flower spikes look like candles, which gives it the name Christmas candle.

Caribbean households used the leaves in two very different ways. Crushed leaves or leaf juice were rubbed on the skin for ringworm and itchy rashes. A leaf tea was swallowed as a strong laxative.

Here is the honest verdict. A few small human trials back the skin use against fungal rashes, but they are weak and short. Long tradition is not proof that a remedy works, nor proof that it is safe.

Taken by mouth, it belongs to the senna family of stimulant laxatives. That use carries real risks, and most of this page's cautions come from it.

How does King of the forest work?

The leaves carry anthraquinones. These are plant compounds that act on gut muscle and, in the lab, on microbes.

On skin, the proposed action is antifungal. In test-tube studies, leaf extracts slow the growth of the fungi behind ringworm and athlete's foot. Whether that same effect happens on human skin is only lightly tested.

A handful of small trials in people with fungal rashes did report improvement. That is suggestive, not settled.

By mouth, the path is better understood. Gut bacteria turn the sennosides into an active form. That form makes the bowel wall contract and draws water into the gut.

The result is a looser, faster stool. This is the same route used by standard senna laxatives. It is also why cramping and fluid loss happen.

Some lab work also reports anti-inflammatory and antibacterial activity in extracts. Those findings come from cells and animals. They have not been shown to matter in people.

What forms does King of the forest come in?

Common forms include:

- Fresh leaves, crushed to a paste and put on the skin - Fresh leaf juice, squeezed and dabbed on a rash - A leaf tea or boiled decoction, swallowed as a laxative - Soaps and shampoos made with leaf extract - Creams, lotions and ointments standardised to a leaf extract strength - Dried leaf powder, capsules and tinctures

The skin products are the most common commercial form. In the Philippines the plant is sold as akapulko lotion for ringworm.

Homemade preparations have no set strength. A cream with a stated extract percentage is more predictable than a leaf you boil yourself.

Where it comes from:

Caribbean folk medicine gave this plant a long and settled place. In Trinidad and Tobago it was called ringworm bush and used against itchy, ring-shaped rashes. In Haiti the name dartrier comes from dartre, an old word for a scaly skin patch.

Healers applied crushed leaves to ringworm, scabies and eczema-type rashes. The leaf tea was taken as a purge to clear the bowels. The same uses were recorded across West Africa, where the plant likely came from, and in Southeast Asia.

The skin use is recorded steadily across many regions and several centuries. That consistency is why the plant is well known. It describes what people did, not what was proven.

What does King of the forest help with?

• Ringworm and other tinea rashes of the skin: This is the plant's best-known use and its strongest evidence. Caribbean healers put crushed leaves straight onto ring-shaped rashes. Small trials in Nigeria and the Philippines tested leaf extract creams against standard antifungal creams. Some reported similar rates of clearing. The trials were small, short and not well blinded. So the use is plausible and partly supported. It is not proven to the standard of a pharmacy antifungal.
• Pityriasis versicolor (a patchy fungal skin rash): Tradition treated the pale or dark patches of this rash like any other skin fungus. Leaf preparations were rubbed on daily. At least one small trial compared a leaf extract with Whitfield's ointment, an older antifungal. The leaf preparation did help some people. The study was small and done at one site. That is a weak base for a firm claim.
• Itchy, scaly rashes and eczema-type skin: Haitian use under the name dartrier covered scaly patches of many kinds. Not all of those patches are fungal. Lab work shows anti-inflammatory activity in extracts. There is no good human trial for eczema or dermatitis. If a rash is not fungal, this plant may simply irritate it. A rash that spreads or weeps needs a doctor, not a leaf.
• Constipation: The leaf tea was used as a purge across the Caribbean. It works through sennosides, the same compounds in standard senna laxatives. Medicinal senna, a close relative, is well proven as a short-term laxative. Senna alata has not been tested the same way in people. So the effect is very likely real but the dose is unpredictable. Stimulant laxatives are meant for short use only. Daily use can leave the bowel sluggish and drop your potassium.
• Scabies and insect bites: Leaf paste was applied to bites, itch and scabies in several traditions. This is folk use alone. There are no useful human trials for these uses. Scabies needs a proven treatment from a clinician, because it spreads through a household.

What are the side effects of King of the forest?

• Stomach cramps and griping pain
• Loose stools or watery diarrhoea
• Nausea
• Fluid loss and low potassium with repeated use
• Yellow-brown or reddish urine, which is harmless
• Dark pigment in the colon lining (melanosis coli) after long use, which fades when you stop
• A sluggish bowel that needs the laxative to work
• Skin stinging, redness or an allergic rash where it is applied
• A rash that gets worse, if it was never fungal

Good to know:

Cramping and loose stools are common with anything swallowed. They are the expected effect, not a rare surprise.

Skin reactions are less common but do happen. Test a small patch first and stop if it burns or spreads.

The serious problems come from long daily oral use. Low potassium can upset your heart rhythm, especially if you also take heart or water pills. Rare reports link long-term anthraquinone laxative use to liver injury.

How much King of the forest should you take?

• Recommended daily: This page gives no personal dose. What follows is only the kind of thing labels carry. Skin creams and lotions are usually sold at a stated leaf extract strength, often in the 20 to 50 percent range, for use once or twice a day on the affected patch. Oral products made from senna leaf are regulated as short-term laxatives in many countries. Their labels set a single small evening amount and warn against daily use. Homemade leaf tea has no set strength. There is no safe way to state an amount for it, so none is given here. Talk to a pharmacist or doctor before taking any senna-type laxative.
• Best time of day: For skin use, timing does not matter much. Most people apply it after washing and drying the area. Senna-type laxatives are usually taken in the evening. They act overnight, so the effect lands in the morning.
• With or without food: Food is not the issue here. Senna-type laxatives are taken with water, usually at night. Drink enough fluid if you are using anything that loosens the bowel. Fluid loss is the main risk. Skin products are unrelated to meals.
• Time to effect: By mouth, a laxative effect usually comes in about 6 to 12 hours. On skin, fungal rashes are slow. Trials measured change over two to six weeks. It may also do nothing. If a rash has not improved after a few weeks, it may not be fungal at all.
• How long to take it: Skin use in the small trials ran for about two to six weeks. For anything swallowed, the rule for senna-type laxatives is short use. Labels generally say no more than about one week without medical advice. Long daily use is where the real harm sits. It can cause low potassium, fluid loss and a sluggish bowel. It can also darken the lining of the colon.