Tropical whiteweed
StarAgeratum conyzoides
Synonyms: Ageratum arsenei, Caelestina suffruticosa, Ageratum suffruticosum, Carelia conyzoides, Carelia brachystephana, Carelia mutica, Ageratum ciliare, Ageratum odoratum, Alomia coelestina, Ageratum koulianum, Ageratum brachystephanum, Ageratum oliveri, Caelestina latifolia, Eupatorium paleaceum, Ageratum sandwicense, Ageratum conyzoides var. inaequipaleaceum, Ageratum conyzoides subsp. latifolium, Carelia latifolia, Ageratum cordifolium, Sparganophorus obtusifolius, Ageratum oerstedii, Ageratum coeruleum, Ageratum hirsutum, Ageratum obtusifolium, Ageratum hirtum, Ageratum nanum, Ageratum muticum, Ageratum album, Phalacraea coelestina, Ageratum humile, Ageratum latifolium var. galapageium, Ageratum conyzoides var. obtusifolium, Eupatorium conyzoides, Ageratum latifolium
Western Herbalism Properties
Traditional Uses
Ageratum conyzoides is widely employed in the folk medicine of Mexico, Central and South America and the Caribbean, particularly Brazil. Fresh crushed leaves are applied as a wound poultice for cuts, burns and skin ulcers, and a leaf decoction is used as a wash for skin irritation, infection and fungal complaints. Infusions of the aerial parts are taken internally as a carminative for stomach upset and colic, for diarrhoea, and as an antispasmodic in fever; the plant has also been used as a febrifuge and as a uterine remedy in some traditional pharmacopoeias. Caribbean practitioners have used the steam from boiled leaves as an inhalation for colds and bronchial complaints. The plant is similarly prominent in West and Central African, Indian (where it features in Ayurvedic and tribal medicine) and Chinese folk pharmacopoeias for very similar indications. No use is recorded for Indigenous peoples of the continental United States in the NAEB.
Gallery
Botanical Description
Ageratum conyzoides is an erect annual herb of the Asteraceae family growing 30-100 cm tall with a slender taproot and aromatic, somewhat goat-scented foliage (whence the name 'goatweed'). Stems are erect, terete, longitudinally ribbed, branched in the upper part and softly covered with spreading white hairs. Leaves are opposite (the upper sometimes alternate), ovate to broadly ovate, 2-8 cm long, with coarsely crenate to serrate margins, an acute to obtuse apex, a rounded to truncate or shallowly cordate base, and softly pubescent and glandular-dotted on both surfaces. Petioles are 1-4 cm long. The inflorescence is a dense, flat-topped corymb of numerous small cylindrical heads borne in the upper part of the plant. Each head is 5-7 mm long with an involucre of two or three rows of narrow, acute, often slightly glandular green bracts. Florets are all tubular, 30-60 per head, with a slender five-lobed corolla 2-3 mm long that is pale lavender-blue (sometimes white or pale pink) and slightly exserted from the involucre. The achene is small, narrowly oblong, black and bears a pappus of five lanceolate awned scales. Native to tropical Central and South America and now pantropical, growing as a weed on disturbed ground, roadsides and fallow fields.
Active Constituents
Precocene I and precocene II
Chromenes (benzopyrans)Concentration: Major components of the essential oil (precocene II often dominant)
The characteristic chromenes of Ageratum, first noted as insect anti-juvenile-hormone ('precocene') agents. They give the plant strong insecticidal and antifungal activity, but precocene II is also hepatotoxic in rodents, causing centrilobular liver necrosis at high doses.
Pyrrolizidine alkaloids (lycopsamine, echinatine and N-oxides)
Pyrrolizidine alkaloidsConcentration: Low but detectable in aerial parts / tea infusions
Hepatotoxic and potentially tumorigenic alkaloids (notably lycopsamine and its N-oxide) detected in the plant and in its medicinal tea. They are the principal safety concern, capable of causing hepatic veno-occlusive disease with chronic exposure.
Polymethoxylated flavonoids (e.g. nobiletin, sinensetin, eupalestin)
Flavonoids (methoxyflavones)Concentration: Abundant in leaves
A rich set of highly methoxylated flavones responsible for much of the plant's anti-inflammatory, antioxidant and antimicrobial activity in laboratory studies.
Essential oil (with beta-caryophyllene and related sesquiterpenes)
Volatile terpenoidsConcentration: ~0.1-0.2% of aerial parts
The aromatic oil, dominated by precocenes plus sesquiterpenes such as beta-caryophyllene, underlies the plant's antimicrobial, insecticidal and nematicidal uses and its characteristic 'goat-like' odour.
Coumarins and phenolic acids
Coumarins / phenolicsConcentration: Minor constituents
Simple coumarins and phenolic acids contributing antioxidant and mild antimicrobial activity to the whole-plant extracts.
⚠ Drug Interactions
Hepatotoxic drugs (e.g. acetaminophen/paracetamol, methotrexate, isoniazid)
The plant contains hepatotoxic pyrrolizidine alkaloids and precocene II, both of which damage hepatocytes; combining it with other hepatotoxic drugs could compound the risk of liver injury.
Clinical note: Avoid internal use with hepatotoxic medications and in anyone with existing liver disease.
Preparation Methods
Fresh leaf poultice / juice (topical)
Parts: leaf, whole aerial plant
Crushed fresh leaves or expressed leaf juice are applied traditionally across Africa, Asia and tropical America to cuts, wounds and skin infections for their antimicrobial and wound-healing effect. Topical use avoids the hepatotoxic risk of oral pyrrolizidine alkaloids.
Leaf infusion / decoction (traditional oral use)
Parts: leaf, flowering tops
An infusion of the aerial parts is used in folk medicine for fever, colic, diarrhoea and inflammation. Because the plant contains hepatotoxic pyrrolizidine alkaloids and precocene, oral use should be short-term and low-dose at most, and is best avoided; it is contraindicated in pregnancy, lactation, children and liver disease.
Essential oil / extract (insecticidal, research)
Parts: whole aerial plant
The precocene-rich essential oil and extracts are used as botanical insecticides, nematicides and antifungal agents in agriculture rather than as internal medicines.
Clinical Studies
Effect of Ageratum conyzoides on Osteoarthritis in an Ageing Adult Population: A Double-Blind Randomized Placebo-Controlled Parallel Study
Seventy adults aged 45+ with osteoarthritis took 250 mg of a pyrrolizidine-alkaloid-free Ageratum conyzoides extract or placebo daily for 12 weeks. The extract significantly reduced total WOMAC and VAS pain scores at weeks 9 and 12 versus placebo, with acceptable safety.
Pyrrolizidine alkaloids in medicinal tea of Ageratum conyzoides
HPLC-HRMS analysis of aqueous extracts of Brazilian A. conyzoides detected hepatotoxic pyrrolizidine alkaloids (lycopsamine, dihydrolycopsamine and acetyl-lycopsamine plus N-oxides) alongside methoxylated flavonoids, prompting the authors to call for toxicological monitoring of its medicinal tea use.
Historical Texts
West African and Central African ethnomedicine (documented ethnobotanical record)
Traditional, documented 19th-20th centuryBrazilian and Amazonian folk medicine ('mentrasto')
Traditional, documented 20th centuryReferences
- Kamboj A, Saluja AK. Ageratum conyzoides L.: A review on its phytochemical and pharmacological profile . International Journal of Green Pharmacy (2008) [DOI]
- Bosi CF, Rosa DW, Grougnet R, Lemonakis N, Halabalaki M, Skaltsounis AL, Biavatti MW. Pyrrolizidine alkaloids in medicinal tea of Ageratum conyzoides . Revista Brasileira de Farmacognosia (2013) [DOI]
- Rao A, Gorman A, Subah S, Muntha S, Bogoda N, Briskey D. Effect of Ageratum conyzoides on Osteoarthritis in an Ageing Adult Population: A Double-Blind Randomized Placebo-Controlled Parallel Study . Nutraceuticals (MDPI) (2025) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
📝 Notes
Public notes from the community and your own private notes on Tropical whiteweed.
No notes yet.