'Bioidentical hormones' is a term created by the lay media to refer to chemicals derived from plants that are modified to be structurally identical to endogenous human hormones. These compounds include estradiol, estrone, estriol, progesterone, testosterone and dehydroepiandrosterone when prescribed for menopausal women. Patients assume bioidentical hormones are natural and safer than synthetic hormones with regard to the risk of developing breast cancer and other diseases, but there is little evidence to support this belief. Proponents of this therapy also support the use of salivary hormone measurements to adjust doses of these hormones instead of adjustment based on improvement or lack of improvement in menopausal symptoms. In this review, the rationale behind the use of bioidentical hormones is discussed, along with the evidence supporting the use of compounded and FDA-approved bioidentical products.