Polygoni Multiflori Radix is the dried root of Polygonum multiflorum Thunb officially recorded in the Chinese Pharmacopoeia as HeShouWu (HSW) in Chinese pinyin. The processed HSW are commonly used in TCM to treat liver disease and Chinese Pharmacopoeia has described the actions of it to tonify liver-kidney, replenish essence and blood, blacken beard and hair, strengthen sinew and bone, and resolve turbidity and lower lipid hence making it use not only as a herbal medicine in TCM but also as supplementary food in health care. Concerns about the hepatotoxicity in association with Polygoni Multiflori Radix and its processed products have been reported in some countries. In the present study, we aim to investigate the potential hepatotoxicity of HSW in rats with oral administration of 95% ethanol-extracts of Polygoni Multiflori Radix by using metabolomics method. Here, male rats with 150-180g body weight were received vehicle control or Polygoni Multiflori Radix extracts (HSW-Ex) orally at 19.2 (low dose), 192 (medium dose), or 1920mg/kg/day (high dose), respectively, for 28 consecutive days. Signs of HSW-induced toxicity were monitored by traditional toxicity assessments (e.g., clinical pathology and histopathology). Metabolomics investigation of serum was performed to identify potential endogenous metabolites which may be relevant to liver injury. Rats received High and Medium dose of HSW-Ex showed greater sign of liver injury with increased levels of ASP, ALT, and AST, as well as reduced SOD activity when compared to vehicle control. In contrast, there are no significant changes relevant to liver injury observed in rats by receiving the low dose of HSW-Ex. Metabolomics analyses have identified ten potential endogenous metabolites varied significantly among the treatment groups with varying doses of HSW-Ex, of which might be related to liver injury. Our data has further suggested that liver damage resulting from HSW-Ex consumption is dosage dependent in rats. It is possible that disruption in amino acid and energy metabolism might lead to subsequent oxidative damage in the liver of rats. Because the clinic practice often use low dose in a short time, therefore HSW usage in TCM still keep safe currently, but we present a warning to the clinical doctors and make them has some concern about high dose of HSW usage in a long term that has potential danger to damage liver. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.