Cryptotanshinone is a quinone diterpene extracted from the traditional Chinese medicine Salvia miltiorrhiza root that shows obvious anticancer activity. The aim of this study was to investigate the mechanism of action of cryptotanshinone as an antigastric cancer agent, as well as a chemotherapy potentiator. A gastric cancer model was established by tumor transplantation, and mice were treated with either 5-fluorouracil or cryptotanshinone, or both drugs. The tumor mass was recorded, and the tumor suppression rate...