Some people may experience diarrhea, dizziness, upset stomach or nausea when taking curcumin. Curcumin rarely causes side effects, and is considered to be likely safe when used in appropriate doses for up to 8 months. Excessive doses of curcumin should be avoided, according to WebMD.
Pregnant women should not use curcumin in medicinal doses, as it may stimulate the uterus or promote a menstrual period, which could cause complications. Nursing women should not use curcumin in medicinal doses, as its safety is not determined, as of 2015. People with a bile duct obstruction or gallbladder problems should not take curcumin. Curcumin may slow blood clotting, so people with bleeding disorders should not take it, notes WebMD.
People with gastroesophageal reflux disease should not take curcumin if it increases symptoms.Those with conditions related to estrogen or hormones should speak to a physician before taking curcumin. People with diabetes should be cautious when using curcumin, as it may decrease blood sugar levels, according to WebMD.
Curcumin may cause infertility. People with an iron deficiency should only use curcumin cautiously, as excessive amounts can prevent the body from absorbing iron. Curcumin may also slow blood clotting and cause extra bleeding, explains WebMD, so it should not be taken within 2 weeks of surgery.