Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 6 4 2021 11 27 160 163 Alireza Asgari Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. Morteza Daraei Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. Sahar KarimpourReihan Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. 2020 09 29 2020 11 08 Many people regard herbal plants as a safe natural product and routinely consume them for maintenance of healthy life or as home remedies without considering their potential health-threatening side effects. Here, we presented manifestations of milk thistle toxicity. The milk thistle’s flavonolignans, especially the silybin ingredient disturb the hemostatic process by dual anticoagulant and anti-platelet properties. This plant can inhibit serine proteases, including factors II and X as in the coagulation cascade as well as platelet activation by blocking adenosine diphosphate receptor and cyclooxygenase; hence, it causes bleeding diathesis. https://crcp.tums.ac.ir/index.php/crcp/article/view/408