Background: Nowadays, more and more herbal drugs of traditional Chinese medicine (TCM) rely on cultivation rather than natural resources because of overexploitation, and the study on quality of cultivated herbal medicines has become a hotspot in the research field of ecology of TCM resources. Though some of molecular biology techniques could improve the contents of secondary metabolites, those chemical compositions may differ from what we require from natural products, resulting in different treatment efficacy. Objective: To explore ways and means of improving TCM quality by means of regulating secondary metabolism from the perspective of natural physiological ecology. Materials and Methods: H 2 O 2 and paraquat as carriers of ROS, propyl gallate as a ROS scavenger, and ethephon as a ROS inductive agent were sprayed on Schisandra chinensis (Turcz.) Baill. Results: The hypo-concentration ROS could enhance the activities of POD, PPO, as well as CAT, and propyl gallate acted on the opposite side, but they all failed to break the homeostasis between ROS and oxidase activity and to exert any effect on the contents of the schisandrin, deoxyschizandrin, and schisandrin B. The hypso-concentration ROS could break the homeostasis, reduce the activities of POD, PPO, as well as CAT, and improve the quality of S. chinensis fruit. The ethephon could effectively improve the quality of S. chinensis without the limitation of metabolic regulation. Conclusion: The conclusions accord with the hypothesis that ROS regulates secondary metabolism.