Anthemis austriaca Jacq. flowers are traditionally used to alleviate abdominal pain, hemorrhoids, ovary diseases and pneumonia. This study aimed to investigate the effects of A. austriaca flowers, which are frequently used in gynecological disorders, on the rat endometriosis model. The rat endometriosis model was used to evaluate the potential activity of the plant in endometriosis. The dried plant material was extracted with n-hexane, ethyl acetate (EtOAc), and methanol (MeOH), successively. The obtained extracts from A. austriaca flowers were applied to the rats. The adhesion scores, endometrial foci areas, and cytokine levels of the peritoneal fluids were measured on surgical induction of endometriosis in rats. The adhesion scores, endometriotic volume, and cytokine levels of the peritoneal fluids were reduced in the EtOAc, MeOH, and buserelin acetate-treated (reference) groups. The MeOH extract reduced the adhesion scores and endometrial foci areas from 3.1 to 1.1 (p < 0.01) and from 86.4 to 40.5 (p < 0.01), respectively and also the MeOH extract reduced tumor necrosis factor (TNF)-alpha, vascular endothelial growth factor (VEGF), and interleukin (IL)-6 levels of the peritoneal fluids from 13.7 to 3.8 (p < 0.01), from 28.4 to 16.3 (p < 0.05) and from 50.2 to 24.3 (p < 0.01), respectively. Therefore, isolation studies were conducted on the EtOAc and MeOH extracts. After the MeOH extract was fractionated using RP-18 column, the obtained subfractions were evaluated again on the endometriosis rat model. Subfractions A and C of the MeOH extract displayed statistically significant activity on the endometriosis rat model. Phytochemical investigation resulted in the isolation of 4-beta-D glucopyranosyloxy-6-methyl-2H-pyran-2-one (1) from Fr. A and quercetin (2), apigenin-7-O-(3 ''-O-acetyl)-beta-D-glucopyranoside (3), apigenin-7-O-(6 ''-O-acetyl)-beta-D-glucopyranoside (4), apigenin-7-O-beta-D-glucopyranoside (5), quercetin-7-O-beta-D-glucopyranoside (6) from Fr. C. Moreover, beta-sitosterol-3-O-beta-D-glucopyranoside (7) was isolated from the EtOAc extract. As a conclusion, the MeOH extract obtained from A. austriaca flowers contributed to the regression of endometriosis. In addition, flavonoids and sterols of the plant were detected as the possible compounds responsible for the activity. (C) 2019 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.