Abstract Objective To study the effect of Lichong Decoction (Lichong Decoction for strengthening anti-pathogenic Qi and eliminating blood stasis) on the expression of insulin-like growth factor-l (IGF-I) and proliferating cell nuclear antigen (PCNA) mRNA in a rat model of uterine leiomyoma. Methods Fifty female Wistar rats were randomized into a normal control group, model group, Lichong Decoction group, Guizhifuling Capsule (Capsule containing Cassia Twig and Poria) group, and Mifepristone group. The uterine leiomyoma model was established by peritoneal injections of exogenous estrogen and progesterone hormone. The ultrastructural changes in cells of rat uterine tissues were observed with transmission electron microscopy, and the expression of IGF-I and PCNA mRNA was detected by real-time fluorescent quantitative PCR. Results Following treatment, cells in the Lichong Decoction group appeared to be arranged normally, the cellular morphology were almost in a normal state, hyperplasia and hypertrophy of the chondrio-some was reduced, collagen fibers were arranged in a regular manner, without obvious hyperplasia, and the expression of IGF-I and PCNA mRNA was significantly decreased compared with the model group (P<0.01). Conclusions The effect of Lichong Decoction on uterine leiomyoma is related to its function in reducing the expression of IGF-I and PCNA mRNA.