OBJECTIVES: To investigate the molecular mechanism by which He's Yangchao Decoction (HSYC) improves ovarian function in a mouse model of premature ovarian insufficiency (POI). METHODS: Forty ICR mice were used to establish a POI model via intraperitoneal injection of cyclophosphamide and were randomly assigned to four groups: model control group, low-dose HSYC group, high-dose HSYC group, and estradiol group (positive control). Additionally, 10 age-matched ICR mice were selected as the blank control group. After intragastric intervention, the ovarian index, serum follicle-stimulating hormone (FSH) levels, and ovarian tissue expression of the FSH receptor (FSHR) were measured. A POI cell model was established by treating the human granulosa tumor cell line (KGN) with 4-hydroxycyclophosphamide. The cells were divided into four groups: solvent control group, HSYC group, inhibitor control group, and inhibitor+HSYC group, which were respectively treated with TH5487 (an OGG1 inhibitor) and HSYC-containing serum. The expressions of OGG1, mitochondrial DNA (mtDNA) oxidative damage markers, and pyroptosis-related proteins were detected by molecular docking, Western blotting, and immunofluorescence. RESULTS: Compared with the blank control group, the model control group showed a decreased ovarian index (P<0.05) and increased serum FSH levels (P<0.01). The ovarian index was higher in both the low- and high-dose HSYC groups compared with the model control group (both P<0.05). FSHR expression in ovarian tissue was lower in the model control group than that in the blank control group, but was higher in the high-dose HSYC group compared with the model control group (P<0.05 or P<0.01). Molecular docking confirmed strong binding affinity between the active components of HSYC and OGG1 (binding energy: －6.3 to －8.3 kcal/mol). Western blotting analysis revealed that OGG1 protein expression in the ovaries of the model control group was significantly reduced compared with the blank control group, while it was increased in the low-dose HSYC group and the estradiol group (P<0.05 or P<0.01). Immunofluorescence results demonstrated that the expression levels of mito-chondrial transcription factor A (TFAM) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) were decreased in the model control group compared with the blank control group (P<0.01), whereas their expressions were significantly elevated in the high-dose HSYC group and the estradiol group (all P<0.01). Cell experiments showed that TH5487 intervention increased the expression of 8-oxoguanine (8-OxoG) (P<0.01), while HSYC-containing serum intervention reduced 8-OxoG expression and increased TFAM expression (P<0.01). The expression of pyroptosis-related proteins (GSDMD, N-GSDMD, caspase-1, IL-1β) increased after TH5487 intervention (P<0.05), whereas HSYC-containing serum suppressed their expression (all P<0.05). CONCLUSIONS HSYC improves POI by upregulating OGG1 expression, mitigating mtDNA oxidative damage, and inhibiting granulosa cell pyroptosis.