AbstractObjectiveTo evaluate the effect of oral diosmin on the incidence and severity of ovarian hyperstimulation syndrome (OHSS) and explore the value of diosmin in preventing and treating OHSS.MethodA retrospective study of women attending a reproductive center in Guangzhou, China, between September and December 2016. The inclusion criterion was previous cancellation of embryo transfer after oocyte retrieval during IVF owing to a high risk of OHSS. The women were divided into two groups depending on whether they received oral diosmin (1000 mg twice daily for 10 days) after oocyte retrieval (diosmin group) or not (control group). Apart from diosmin, both groups underwent the same treatment. Baseline information and data related to OHSS were compared.ResultsOverall, 146 women were included: 74 in the diosmin group and 72 in the control group. The incidence of moderate‐to‐severe OHSS in the diosmin and control groups was 5/74 (6.2%) and 14/72 (13.4%), respectively (P=0.027). The control group included four cases of paracentesis due to ascites; there were no cases of paracentesis or severe OHSS in the diosmin group.ConclusionOral administration of diosmin effectively reduced both the incidence of moderate‐to‐severe OHSS and the severity of OHSS among high‐risk women.