Troxipide is widely used to treat gastric ulcer (GU) in the clinic. However, a lack of systematic metabolic, pharmacokinetic and pharmacological studies limits its clinical use. This study aimed to firstly explore the metabolic, pharmacokinetic and pharmacological mechanisms of troxipide in rats with GU compared to normal control (NC) rats. First, metabolic study was perormed by a highly selective, high-resolution mass spectrometry method. A total of 45 metabolites, including 9 phase I metabolites and 36 phase II metabolites, were identified based on MS/MS spectra. Subsequently, the pharmacokinetics results suggested that the C max , K a , t 1/2 , AUC (0−t) and AUC (0−∞) of troxipide were significantly increased in rats with GU compared with NC rats. The V z , K 10 and absolute bioavailability of troxipide were obviously decreased in rats with GU compared with NC rats, and its tissue distribution (in the liver, lung and kidney) was significantly different between the two groups of rats. Additionally, the pharmacodynamic results suggested that the levels of biochemical factors (IL-17, IL-6, TNF-α, IFN-γ, AP-1, MTL, GAS, and PG-II) were significantly increased, the PG-Ӏ level was obviously decreased, and the protein expression levels of HSP-90, C-Cas-3 and C-PARP-1 were markedly increased in rats with GU compared with NC rats. The above results suggested that the therapeutic mechanisms underlying the metabolic, pharmacokinetic and pharmacological properties of troxipide in vivo in rats deserve further attention based on the importance of troxipide in the treatment of GU in this study, and these mechanisms could be targets for future studies. Gastric ulcer, (GU) a common disease in the clinic, is a peptic ulcer that affects humans of all ages. It is associated with morbidity and mortality, and has become a medical-social problem of global importance that has received increased attention 1-4. The frequent occurrence of GU between the cardia and pylorus mainly results form tissue damage caused by digestive juices decomposing the gastric mucosa, especially near the lesser curvature of the stomach and gastric antrum 5-8. Currently, GU is a widely considered multifactorial disease because it is related to gastric acid, gastric pepsin, infection, physical fitness, environment, living habits and so on 9-11. If not treated adequately, GU can lead to serious complications such as perforation and bleeding 12-15. In addition, the acetic acid-induced GU in rats is most similar to GU in humans 16-20. Here, acetic acid-induced GU is more severe than other GU models (ethanol-, ligation-and reserpine-induced models), and is the most commonly used model for experimental research on GU 21,22. Moreover,this model is reproducible and reliable. Therefore, we selected a rat model of GU to evaluate relative studies of troxipide in the paper. Troxipide (3,4,5-trimethoxy-N-3-piperidinyl, Fig. 1), a defensive factor-enhancing therapeutic agent for gastritis and GU that exerts inhibitory, therapeutic and preventive effects to specifically tho...