Yerba Mate
Ilex paraguariensis
Edible plantPhoto credit: Franz Eugen Köhler, Köhler's Medizinal-Pflanzen
Safety information
Safety information
Toxicity: Contains caffeine (~0.7-2%) and theobromine — overconsumption causes insomnia, tachycardia, anxiety, GI upset. IARC (1991) classified 'hot mate' Group 2A; the 2016 re-evaluation attributes the esophageal-cancer risk primarily to drinking at very hot temperatures (>65 C). PAHs from smoke-drying may add contaminant risk.
Contraindications: Caffeine sensitivity, arrhythmia, uncontrolled hypertension, anxiety disorders, pregnancy/breastfeeding; avoid scalding-hot to reduce esophageal risk.
Interactions: Additive stimulation with other caffeine sources; potential MAO-inhibitor interaction; affects CYP1A2-metabolized drugs (caffeine); caution with stimulants, ephedrine, theophylline.
Pregnancy & breastfeeding: Caution in pregnancy/breastfeeding.
Evidence level
Supported by clinical trials in humans.
Preparations
tea bags; extracts · dried leaves
Part used: dried leaves
hot or cold water infusion drunk through a bombilla · dried leaves
Part used: dried leaves
Traditional use: stimulant and tonic for fatigue, mental/physical performance; appetite/weight control; diuretic; digestive aid
Proposed mechanism: polyphenols (chlorogenic acid), flavonoids, xanthines (caffeine, theobromine), saponins — antioxidant and metabolic
Dosage note (descriptive only): avoid scalding-hot (>65 C) to reduce esophageal risk
Associated conditions
Edibility
Edible parts: Leaves used only as a steeped beverage (not eaten whole).
Toxic lookalike warning
Avoid wild-foraged unidentified holly — many Ilex species (I. aquifolium) have toxic emetic berries; never substitute ornamental holly.
Nutritional notes
Polyphenols (chlorogenic acid), flavonoids (quercetin, rutin, kaempferol), saponins, xanthines (caffeine, theobromine), minerals (P, Fe, Ca), vitamins C, B1, B2.
Healing traditions
Sources (2)
- Mate Drinking and Esophageal SCC (pooled case-control), Cancer Epidemiol Biomarkers Prev, 2014
- Yerba Mate antioxidant compounds, PMC8868397, 2022