Background: Due to the toxicity of chemotherapy drugs in cancer patients, thrombocytopenia can lead to bleeding. Trifolium pratense L. is traditionally used as an anti-inflammatory compound for the treatment of various diseases. The aim of the present study was to evaluate the effect of T. pratense (red clover) extract (TPE) on thrombocytopenia and the related factors in a rat model of chemotherapy.
 Materials and Methods: In this experimental in vivo study, 28 rats were randomly divided into four groups of seven members (four males and three females) including Group1 as the control subjects, Group2 as thrombocytopenia cases, and Groups 3 and 4 with thrombocytopenic animals receiving TPE (100 and 200 mg/kg). Thrombocytopenia was induced by intraperitoneal injection of cyclophosphamide (CP) on three consecutive days. Then, the TPE was fed to rats for 14 days. At the end of the study, the rats' weight was measured. Blood samples were collected, complete blood count (CBC) was performed, and PF4 and clotting time were measured. After the dissection of the animals, the bone marrow and spleen were separated, and hisopathological changes were determined. The data were analyzed by one-way ANOVA and a post-hoc Tukey test.
 Results: Cyclophosphamide decreased the platelets and the white blood cells (WBCs) and increased PF4 and the clotting time significantly (P < 0.05). Also, TPE significantly increased the platelets and the WBC counts but decreased the time of clotting and the PF4 factor (P < 0.05). TPE increased megakaryocyte (P < 0.001) and enhanced the bone marrow and spleen cellularity.
 Conclusion: T. pratense can increase the number of platelets and WBCs and improve thrombocytopenia and bone marrow cellularity induced by chemotherapy.