Green tea
Camellia sinensis (L.) KuntzeTheaceae // leaf
Overview
Plant parts
leaf
Known constituents
caffeine, EGCG and other catechins
Research corpus coverage
Chemistry notes
- CHEMISTRY: Relevant reported constituents include caffeine; EGCG and other catechins; constituent presence alone does not establish clinical efficacy.
Uses & Evidence
Traditional / historical use
Documented traditional use — not a claim of established efficacy.
TRADITIONAL: Green tea has been used for alertness; metabolic and cardiovascular health; this records historical/traditional use and does not establish efficacy.
MODERATE · evidence synthesis/fact sheet · NCCIH Herbs at a Glance
Modern evidence
EVIDENCE: For the major use set (alertness; metabolic and cardiovascular health), the evidence assessment is limited/mixed: Limited/mixed evidence for weight and cardiometabolic outcomes; no established cancer-prevention effect.
MODERATE · regulatory monograph and mixed scientific literature · NCCIH Herbs at a Glance
Mixed findings, product heterogeneity, or indirect evidence are preserved in the detailed profile.
Preparation
Forms used traditionally
A listed form does not imply it suits every plant part, or that one preparation is interchangeable with another — see the plant’s own notes below.
PREPARATION: The medicinal material is leaf; traditional and modern forms include infusion/tea, tincture, powder/capsule, extract. No dose or potency is specified.
MODERATE · regulatory monograph · EMA European Union herbal monographs and list entries
Preparation-specific evidence should not be generalized across extracts, teas, oils, or whole herb.
Safety
Dogs
- High risk
Green-tea polyphenols, primarily EGCG, were associated with increased toxicity in fasted dogs, including severe gastrointestinal irritation, weight loss, and mortality; feeding reduced toxicity.
Intrinsic toxicity · OTHER · green-tea polyphenols, primarily EGCG · HIGH · peer_reviewed_veterinary · The Role of Plant Extracts in Enhancing Nutrition and Health ...
- Caution
Non-fasted dogs had lower and less variable exposure to green-tea polyphenols and reduced toxicity compared with fasted dogs.
Intrinsic toxicity · OTHER · green-tea polyphenols · MODERATE · peer_reviewed_veterinary · The Role of Plant Extracts in Enhancing Nutrition and Health ...
- Low concern
Orally administered green-tea catechins, including EGCG and ECG, were well tolerated in Beagle dogs at the reported exposure, with no significant toxicity reported.
Intrinsic toxicity · ORAL · green-tea catechin/polyphenol preparation · MODERATE · peer_reviewed_veterinary · The Role of Plant Extracts in Enhancing Nutrition and Health ...
Additional safety notes (general, unstructured)
Free-text safety notes carried from their source — not broken out by species, route, or hazard type, and not equivalent to the structured records above. Each note names the kind of source it came from.
SAFETY: Major issues include Caffeine effects; concentrated extracts can cause serious liver injury. Contraindications/cautions include Liver disease; caffeine sensitivity.
HIGH · observational/case series and expert review · LiverTox: Herbal and Dietary Supplements
SAFETY: Clinically relevant interaction concerns include Interacts with stimulants, warfarin (vitamin K variability), nadolol, iron absorption and some drugs via transporters.
MODERATE · observational/case series and expert review · LiverTox: Herbal and Dietary Supplements
Some interactions are theoretical or based on case reports/pharmacokinetics rather than outcome trials.
SAFETY: Pregnancy/lactation reference: Limit concentrated extracts in pregnancy/lactation; caffeine exposure is relevant.
MODERATE · regulatory monograph or evidence synthesis · NCCIH Herbs at a Glance
Absence of evidence is not evidence of safety.
Green-tea polyphenols, primarily EGCG, were associated with increased toxicity in fasted dogs, including severe gastrointestinal irritation, weight loss, and mortality; feeding reduced toxicity.
HIGH · peer_reviewed_veterinary · The Role of Plant Extracts in Enhancing Nutrition and Health ...
The page does not specify the route or exact preparation concentration in this comparison.
Non-fasted dogs had lower and less variable exposure to green-tea polyphenols and reduced toxicity compared with fasted dogs.
MODERATE · peer_reviewed_veterinary · The Role of Plant Extracts in Enhancing Nutrition and Health ...
Reduced toxicity does not establish that the preparation is risk-free; route and exact dose are not specified.
Orally administered green-tea catechins, including EGCG and ECG, were well tolerated in Beagle dogs at the reported exposure, with no significant toxicity reported.
MODERATE · peer_reviewed_veterinary · The Role of Plant Extracts in Enhancing Nutrition and Health ...
Dose- and preparation-specific finding; it does not establish safety for all green-tea products.
Preparation × species risk matrix
Unknown means insufficient evidence was located — not that a form is safe.
Cats
- tinctureCaution
- concentrated extractUnknown
- essential oilUnknown
- glyceriteUnknown
- infused oilUnknown
- salveUnknown
- smoke/combustionUnknown
- tea/infusionUnknown
- whole herbUnknown
Dogs
- tea/infusionHigh risk
- tinctureCaution
- concentrated extractUnknown
- essential oilUnknown
- glyceriteUnknown
- infused oilUnknown
- salveUnknown
- smoke/combustionUnknown
- whole herbUnknown
Identity
- Synonym
GBIF resolves Thea sinensis L. as a synonym of Camellia sinensis. The older name still appears in herbal and taxonomic literature.
HIGH · GBIF Species Match API
Botanical synonym
Thea sinensis L.
Taxonomic identity note
- Green tea is treated here as Camellia sinensis (L.) Kuntze in the family Theaceae; recorded older names include Thea sinensis L..
Sources
Research records are source-linked but may not yet be editorially reviewed.
peer_reviewed_veterinary
- NCCIH Herbs at a Glance3 claims
NCCIH fact sheet
NIH LiverTox monograph
- Plants of the World Online1 claim
botanical taxonomy database
EMA monograph
WHO monograph
- GBIF Species Match API1 claim
authoritative taxonomic database