Answer： According to the 1.4 academic literature of the "Guidelines for Collection and Reporting of Adverse Drug Reactions in Individual Cases", holders should search widely used literature databases, such as China National Knowledge Infrastructure (CNKI), VIP, Wanfang Database, and other domestic literature databases, as well as PubMed, Embase, Ovid, and other foreign literature databases. Both domestic and foreign literature require at least two databases to be searched simultaneously. There is no distinction between varieties sold only domestically and varieties sold both domestically and internationally. Therefore, in order to ensure compliance, it is necessary to conduct literature searches strictly in accordance with regulatory requirements. Secondly, conducting searches globally can also comprehensively detect whether similar products have relevant cases or risk reports, in order to more comprehensively identify and evaluate the risk of this product and similar products. According to the Notice of the State Food and Drug Administration on the Writing Standards for Regular Drug Safety Update Reports (Guo Shi Yao Jian An [2012] No. 264), All first and follow-up reports of individual adverse drug reactions occurring both domestically and internationally during the reporting period should be reported, including not only those collected through the spontaneous reporting system, but also those discovered through post market research and other organized data collection projects, as well as those reported in the literature. For companies that do not clearly identify drug manufacturers in the literature, relevant companies should report. Therefore, A comprehensive search of professional literature is beneficial for holders to have an overall understanding of the safety characteristics of the products they hold. It is not only suitable for holders to independently collect individual case reports, but also for improving the content of PSUR reports.