Reference summary — not medical advice or a personal risk estimate.
Aflatoxins
Quick answer
Classified as Group 1 — carcinogenic to humans, based on sufficient evidence in humans. Eaten. A toxin made by moulds on crops such as maize, peanuts and tree nuts, mostly in warm, humid regions. Also found in meat and dairy from animals fed contaminated feed. Farm workers can breathe in dust from contaminated crops and feed.
Summary
Toxins from molds that grow on improperly stored grains, peanuts and corn are associated with increased liver cancer risk.
Detail
Aflatoxins are mycotoxins produced by Aspergillus moulds that contaminate staple foods (especially maize, peanuts and tree nuts) when stored in warm, humid conditions. IARC classifies aflatoxins as Group 1 with sufficient evidence for liver cancer (hepatocellular carcinoma). Regulated food-safety limits in high-income regions keep dietary exposure low; the highest exposures are in low- and middle-income tropical regions where post-harvest storage favours mould growth.
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
regional
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
EPA
US EPA — Integrated Risk Information System (IRIS) carcinogen assessments
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.