What is Black sage?

Black sage is a wild shrub of the Caribbean, known in science as Cordia curassavica. In Barbados and Trinidad people call it wild sage or black sage bush. It is not the kitchen sage you cook with.

The leaves and soft stems are the parts used. They are brewed as a bush tea, added to bush baths, or crushed onto sore skin. In Brazil the same plant is called erva-baleeira, and its oil is made into a rub.

Here is the honest verdict. One product has been tested in people: a Brazilian skin cream made from the plant's oil. It was tried for muscle and tendon pain.

The teas, baths and poultices have not been tested this way. Long use in folk medicine is not proof that a remedy works. It is not proof that it is safe.

How does Black sage work?

Most of what is known about black sage comes from the lab bench, not from people.

The leaf oil is rich in two scent compounds, alpha-humulene and trans-caryophyllene. In animal and cell studies, both appear to damp down swelling and pain signals. In cell studies, caryophyllene also binds a receptor called CB2, which is linked to inflammation.

Whether that explains the results seen with the Brazilian skin cream is not settled. For the tea, no mechanism has been shown in people at all.

In test tubes, extracts of the leaf slow the growth of some bacteria and fungi. Whether that happens on human skin, or in the gut, has not been shown.

What forms does Black sage come in?

You will meet black sage in a few forms. Some come straight from the leaf.

- Fresh or dried leaf, brewed as a bush tea. - Leaf bundles added to a bush bath. - Crushed leaf used as a poultice on the skin.

Others are made and sold as products.

- Essential oil, sold for scent or for diluted skin use. - A registered 0.5 percent oil cream sold in Brazil for muscle pain. - Tinctures and capsules, mostly from small herbal sellers.

Strength varies a lot between batches of leaf. Wild-picked bush tea is not standardised in any way.

Where it comes from:

Black sage has a long place in Caribbean bush medicine. Records from Barbados and Trinidad describe the leaf tea for colds, chest congestion, fever and upset stomach.

Healers also used the leaves in bush baths, which were taken for aches, skin trouble and for cleansing in a spiritual sense. Crushed leaves were laid on cuts, boils and sores.

In Brazil the same shrub was used by coastal and Indigenous communities for pain and bruises. That use led to modern study of the leaf oil. None of this history tells you the plant is safe for you to use on your own.

What does Black sage help with?

• Muscle and tendon pain (as a skin cream): This is the only use with real human data. Small Brazilian trials tested a cream made from the leaf oil on tendinitis (a sore, swollen tendon) and muscle pain. Users reported less pain, with results close to a standard anti-inflammatory gel. The trials were small and tied to the maker of the product. The findings apply to that cream, not to home-made oils or teas.
• Colds, coughs and chest congestion: A long-standing Caribbean use for the leaf tea, often sweetened and drunk hot. No human trial has tested it for colds. Warm fluid and steam can ease a stuffy nose on their own. That comfort may explain much of what people notice.
• Upset stomach and gas: Tradition held that the bitter tea settled the belly and moved trapped wind. Lab work shows the oil can relax smooth muscle in animal tissue. There is no human study of black sage for stomach complaints.
• Minor skin sores and itching: Healers laid crushed leaves on cuts, boils and rashes. In test tubes, leaf extracts slow some bacteria and fungi. Whether that helps a real wound heal has not been shown. Plant poultices can also carry dirt and germs into broken skin.
• Fever: Bush tea and bush baths were used to break a fever. No trial has tested this. A fever that climbs or lasts needs medical care, not bush tea.

What are the side effects of Black sage?

• Nausea or stomach upset from the tea
• Skin redness, burning or itching where a cream or poultice was used
• Allergic rash, in people sensitive to borage-family plants
• Possible liver strain with long, heavy use (not well measured)

Good to know:

Short, occasional use of the tea seems to be tolerated by most people, but no good safety study backs that up.

The skin cream caused mild redness or itching in a small share of trial users. The serious concern is not a short-term side effect. It is the unmeasured risk to the liver from long daily use of a borage-family plant.

How much Black sage should you take?

• Recommended daily: There is no agreed amount for black sage, and this page gives you no personal dose. For bush tea, sellers of dried leaf often list about 1 to 2 grams of leaf per cup. That is a label figure, not advice for you. The Brazilian skin cream is standardised at 0.5 percent leaf oil, and its own label sets how much to use. Wild-picked leaf has no such standard, so the strength of a home brew is unknown. The essential oil should never be swallowed.
• Best time of day: Time of day does not matter much. The tea was often drunk hot at night, and bush baths were taken in the evening. Pick whatever fits your day.
• With or without food: Black sage tea is bitter and can sit badly on an empty stomach. Many people drink it after food. Creams and baths have nothing to do with meals.
• Time to effect: The Brazilian skin cream was tested over one to three weeks in trials. For the tea, no one can give an honest time. Any comfort from a hot drink comes within minutes, but that is the warmth as much as the herb. It may also do nothing at all for you.
• How long to take it: Short use only. Because the borage family link to liver-harming compounds has not been ruled out, daily use for weeks or months is not a good idea. A few days is the usual pattern in folk use for a cold or a sore belly. If you are thinking of a longer course, ask a doctor or pharmacist first.