Abstract: Gynura Segetum is one of the familiar medicinal herbs in China, alias Gynura japonica. It has the effects of hemostasis, detoxification and swelling. It is often misused because its rhizome is very similar to that of Panax notoginseng of the Araceae family. There have been a number of cases of Gynura Segetum induced hepatic sinusoidal obstruction syndrome(HSOS) in China, but there is still a lack of effective treatment strategies. Studies have shown that pyrrolidine alkaloids are the main toxic components in Gynura Segetum causing HSOS. With the deepening of the research on HSOS, the main causes and hepatotoxicity mechanisms of Gynura Segetum induced HSOS were further summarized by reviewing the existing literature in recent years. Among them, including oxidative stress and inflammation, endoplasmic reticulum stress, apoptosis, autophagy, metabolic enzymes, bile acid metabolism dysfunction, TSP1-CD47 pathway, intestinal flora and so on. This paper aims to understand the toxic mechanism of Gynura Segetum and improve the understanding of HSOS, and provide suggestions for further exploring effective treatment of the disease.