Background/aim: Ankaferd blood stopper (ABS) is a mixture of certain ratios of 5 different plant roots (Thymus vulgaris, Glycyrrhiza glabra, Vitis vinifera, Alpinia officinarum, and Urtica dioica). The aim of this study is to evaluate the histopathological effects of ABS on articular cartilage in vitro. Materials and methods: Twenty-one albino Sprague Dawley rats were randomly allocated to 3 groups: 0.1 mL of saline was injected in the first group, 0.1 mL of ABS was injected in the second group, and 0.1 mL of blood and 0.1 mL of ABS were injected in the third group. One month later all rats were sacrificed. Specimens were obtained for histopathological evaluation. Results: Significant results were detected in the groups with respect to International Cartilage Repair Society and synovial proliferation scores (P < 0.05 and P < 0.01). According to inflammatory cell infiltration and fibrin formation scores, there was no significant difference between group 1 and group 2 (P < 0.01), although there was significant difference between group 3 and the other groups (P > 0.05). Conclusion: ABS and hemarthrosis had toxic effects on knee cartilage. The side effects were increased with the combination of hemarthrosis and ABS. As a result, ABS had unexpected effects on experimental hemarthrosis.