Diets of mice containing 0.5% turmeric or 0.015% curcumin did not show significant increases in the incidences of micronucleated polychromatic erythrocytes, aberrations of bone marrow chromosomes, alterations of pregnancy rate or embryo survival, among others. At LOAEL values of 400 mg/kg bw/day or higher (2000 mg/kg bw/day), enlargement of the liver, ulcers, and hyperplasia in the gastrointestinal tract have been observed. Toxic activity is related to inhibition of the cytochrome P-450 enzymes.