Reported side effects are uncommon and are generally limited to mild stomach distress. There is some evidence to suggest that turmeric extracts can be toxic to the liver when taken in high doses or for a prolonged period of time.[28], [29] For this reason, turmeric products should probably be avoided by individuals with liver disease, heavy drinkers, and those who take prescription medications that are hard on the liver.

Curcumin was found to be pharmacologically safe in human clinical trials with doses up to 10 g/day.[30] A phase 1 human trial with 25 subjects using up to 8000 mg of Curcumin per day for 3 months found no toxicity from Curcumin. Five other human trials using 1125-2500 mg of Curcumin per day have also found it to be safe.[31]

Do not use this supplement if you have gallstones or during pregnancy. There is a possibility of allergic contact dermatitis from turmeric.