Aristolochic acid (in some herbal products)

Tier 4 — risky / avoid · Kidney cancer · Nephrotoxicity

Classified as a confirmed human carcinogen by international cancer authorities. WHO warns it causes irreversible kidney damage that progresses to bladder cancer. Found in some traditional Chinese and Ayurvedic herbal products, sometimes under names like "mu tong" or "fang ji." There is no safe dose. Always check herbal product ingredient lists carefully.

Dose: ZERO safe dose — avoid "mu tong," "fang ji," or "Aristolochia"