Reference summary — not medical advice or a personal risk estimate.
Aristolochic acid
Quick answer
Classified as Group 1 — carcinogenic to humans, based on sufficient evidence in humans. Eaten. In some traditional herbal preparations and supplements containing Aristolochia species. Several countries have withdrawn these from the market.
Summary
A toxin in some traditional herbal medicines linked to kidney and urinary-tract cancers.
Detail
Aristolochic acid and plants containing it (Aristolochia species) are classified Group 1 by IARC with sufficient evidence for cancers of the renal pelvis, ureter and urinary tract. Exposure is largely through traditional herbal preparations and supplements that contain Aristolochia. Several national regulators have withdrawn Aristolochia-containing products from the market.
What's not established
This classification is based on sufficient evidence in humans that this factor can cause cancer. It does not establish a safe exposure threshold, your personal risk, or how this factor's risk compares in size to other Group 1 agents — hazard classifications are not ranked by magnitude.
Regional relevance
global
Documented in these products
Presence in a product category doesn't imply the product causes cancer. Click each to see the source and context.
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
NCI
NCI — Cancer-Causing Substances in the Environment
IARC
IARC Monographs — Classifications by Cancer Site, Vols 1–140
Supporting sources
ACS
ACS — Known and Probable Human Carcinogens
NTP
NTP — Report on Carcinogens (US National Toxicology Program)
WCRF/AICR
WCRF/AICR — Diet, Nutrition, Physical Activity and Cancer: a Global Perspective (Third Expert Report)
WCRF/AICR
WCRF — Cancer Prevention Recommendations
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.