Guaco
Mikania glomerata
Photo credit: Eugenio Hansen, OFS
Safety information
Safety information
Toxicity: Generally low toxicity at traditional doses; high coumarin intake carries theoretical hepatotoxic and anticoagulant/bleeding risk; coumarin content varies widely between batches (quality-control issue).
Contraindications: Pregnancy/breastfeeding (insufficient data); bleeding disorders; before surgery; concurrent anticoagulants.
Interactions: Anticoagulants/antiplatelets (warfarin) — additive bleeding risk via coumarin; other coumarin/anticoagulant herbs; theoretical interaction with hepatically metabolized drugs.
Pregnancy & breastfeeding: Pregnancy/breastfeeding: insufficient data.
Evidence level
Supported by laboratory or animal studies; not yet confirmed in humans.
Preparations
tinctures, standardized extracts · leaves
Part used: leaves
leaf infusion/syrup (xarope de guaco) · leaves
Part used: leaves
Traditional use: bronchodilator, expectorant, cough suppressant for bronchitis, asthma, colds/flu; anti-inflammatory; antiophidic (folk)
Proposed mechanism: coumarin marker constituent (~50-60% of bronchodilating activity, lung smooth-muscle relaxation); anticoagulant activity
Dosage note (descriptive only): coumarin content varies widely between batches
Associated conditions
Nutritional notes
Not a food source; coumarin, diterpenes, kaurenoic acid, flavonoids.
Healing traditions
Sources (2)
- Mikania laevigata and M. glomerata pharmacological tool, J Pharm Pharmacol, 2010
- Biological Activities of Mikania scoping review, PMC12030693, 2025