Estrogen is a naturally occurring hormone and isn’t a bad thing, but your body needs to have a healthy balance. Too much or too little can be problematic. In basic terms, something that is estrogenic can mimic or enhance the body’s level of estrogen. If you are pregnant or breastfeeding, estrogenic oils should be avoided because your levels are already high, and adding to that can have detrimental effects. If you have certain conditions such as endometriosis, or estrogen-sensitive cancer, you should also steer clear of estrogenic essential oils.