The occurrence of chemicals of natural origin that possess the capacity to mimic the hormonal properties of estrogen has been previously reported in the biomedical literature. From these reports, it is apparent that the structural nature of these estrogen mimics is very diverse. This estrogen mimic can be found in plants used in the treatment of health conditions as alternative medicine, such as the treatment of symptoms associated with menopause. Many of these plants have been investigated, but there still exist many instances in which estrogenic activity is unsuspected and exposure unknown. This research focuses on Trigonella foenum-graceum (Fabaceae), commonly known as Fenugreek, which has been used since antiquity as a galactogogue to increase milk production in nursing women. It has been suggested that Fenugreek contains phytoestrogens responsible for this galactogogic activity. Although previous reports support Fenugreek’s estrogenic activity and many of its complex chemical constituents have been elucidated, no specific chemical responsible for the purported estrogenic activity has been identified with certainty. The objective of this investigation is to study the chemistry of Fenugreek for estrogenic activity and using a bioassay-guided approach to isolate and elucidate principle(s) associated with the putative hormonal activity. For the chemical and estrogenic study of Fenugreek, seeds were ground up and extracted with organic solvents of various polarities. Further fractionation of extracts was performed with the use of Sephadex LH-20 column chromatography and preparative Thin Layer Chromatography (TLC). The chemistry in these extracts has been explored using TLC and various diagnostic spray reagents for composition profiles. These crude extracts were used to test for estrogenic activity and further chemical elucidation. The estrogenic activity was assayed using the strain YGY13 of Saccharomyces cerevisiae transformed with the plasmid pGEV-HIS3, which contains the human estrogen receptor and a ?-galactosidase reporter gene. Initial investigation of Fenugreek revealed the presence of the steroidal saponin Diosgenin in the active chloroform/methanol extract as shown by the use of the Liebermann-Burchard reagent and an authentic sample, as well as, the use of mass spectrometry. Sequential bioassay guided fractionation of this extract revealed the presence of additional non-steroidal estrogenic constituents resulting in the detection by mass spectrometry of a family of isoflavones. This is the first time that the presence of these isoflavones in Fenugreek have been directly associated with its estrogenic activity. The Acetylcholinesterase inhibition activity of Fenugreek was explored using an in vitro bioautographic method on TLC, and the antibiotic properties were assayed against yeast as a test organism. Extracts of fenugreek were found to possess both pharmacologic activities.