This issue of the Journal of Cell Communication and Cell Signaling on hormetic mechanisms represents an important step in the evolution of the hormesis dose response concept. Since its modern resurgence in the late 1970s the widespread occurrence of hormesis has been in search of its underlying mechanisms. The present integrative set of papers builds upon significant recent advances in the elucidation of hormetic mechanisms and provides the reader with a deep and extensive view of the concept of hormesis from a broad range of researcher perspectives and in many biomedical applications.