Avoid during pregnancy, nursing, pelvic inflammatory disease and excessive menstrual bleeding. Not for long term use; do not exceed recommended dose of 1.5 grams of dried herb in tea, 2 to 3 times daily. Thujone, a constituent of Wormwood, is neurotoxic but the primary references do not substantiate toxicological concern, except with long-term use, excessive dose (which is more likely with an extract), or use of the essential oil.