Figure 1.

(A) Bell-like curve depicting the optimal dose or time of an exposure. Time not only refers to the total duration but also includes the temporal pattern as defined by frequency and interval. (B) An artificial setting of the baseline leads to a biphasic curve aligned with the classic definition of hormesis - low-dose beneficial effects of harmful substances. The transformation of the adverse effect to the favorable effect exemplifies how ‘illness is the doorway to health’ as articulated in the ancient philosophy of Yin and Yang.