Saliva is an excellent medium for the measurement of the biologically active fraction of steroid hormones in the bloodstream because it is a natural ultrafiltrate of blood, and steroids not bound by carrier proteins in the blood freely diffuse into saliva. The baseline measurement of hormone levels in saliva provides an accurate assessment and can be used to identify or monitor a number of clinical conditions, including climacteric changes in perimenopausal or postmenopausal women, adrenal disorders such as Addison's disease or Cushing's disease, and androgen deficiency in men and women, the age-related decrease of hormones such as testosterone and dehydroepiandrosterone can also be assessed and monitored. When compared with serum testing, saliva testing offers several advantages. Saliva collection is simple, noninvasive, stress free, painless, and safe for the patient and practitioner. The collection time for saliva testing is more controllable than that for serum testing. The transport of saliva samples for assessment can be accomplished inexpensively via the U.S. Postal Service because hormones are stable in saliva for three weeks at room temperature, and the cost of that testing is covered by many insurance plans. In this first of a two-part series, we discuss the clinical use and basic elements of saliva testing and provide guidelines for postreatment interpretation by compounding pharmacists.