Concentrations of curcumin—an active ingredient in turmeric—are higher in supplements than in foods and may cause stomach upset when taken in large doses, as well as diarrhea, skin rash, yellow stool, and headache.
Turmeric is generally considered safe when eaten in foods, consumed as an oral supplement, or applied to the skin in recommended amounts. Concentrations of curcumin—an active ingredient in turmeric—are higher in supplements than in foods and may cause stomach upset when taken in large doses, as well as diarrhea, skin rash, yellow stool, and headache.