ABSTRACT: The present study was designed to elucidate the underlying mechanisms of Bao Gui capsule (BGC) against hyperandrogenism, insulin resistance and leptin resistance of PCOS. Letrozole was used to induce a PCOS model in rats, which were then randomly divided into four groups (n=9): Control, Model, high‑dose BGC (BGC‑H) and low‑dose BGC (BGC‑L) group. Serum levels of follicle‑stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), estradiol (E2), insulin, leptin, and interleukin (IL)‑1β, IL‑6 and tumor necrosis factor‑α (TNF‑α) in the hypothalamus were determined by ELISA. Protein levels of cytochrome P450c17α and cytochrome P450 aromatase (P450arom) in ovaries were determined by immunohistochemistry and western blot analysis. Additionally, the expression of GLUT4 in uterus and muscle tissue, and NF‑κB, IKKβ and SOCS3 mRNA levels in the hypothalamus were evaluated. BGC significantly reduced body weight gain and decreased serum levels of LH/FSH, T, log T/E2, insulin and leptin compared with the PCOS model rats. Furthermore, BGC markedly reduced the expression of P450c17α and significantly increased the expression of P450arom in ovaries, and increased the expression of GLUT4 in uterus and muscle tissues. BGC also effectively reduced the level of IL‑6 and TNF‑α, and the expression of IKKβ, NF‑κB and SOCS3 in the hypothalamus of PCOS model rats. These results suggest that BGC may effectively improve hyperandrogenism, insulin resistance, endometrial receptivity and the low‑grade chronic inflammation in the hypothalamus.