Abstract: Hormesis, a biphasic dose-response phenomenon characterized by low-dose stimulation and high-dose inhibition, is a common feature of medicines but neglected sometime. Understanding of hormesis is essential for drug discovery and clinical application. Assessing hormetic range needs a proper experiment design including the number of doses and dose spacing, especially in the low dose zone. This article provides the shapes of hormetic dose-response curves, underlying mechanisms and the significance of hormesis for drugs of infectious diseases to facilitate drugs development and clinical applications.