Abstract
Estimating functions to predict dose-response functions below available experimental or epidemiological data is a great cause of controversy and economic impact. Information entropy is used to evaluate different forms of dose-response function for doses below epidemiological and experimental levels. When both the threshold dose and the mean response at some upper-end dose are known, the maximum-entropy dose-response function is found to be a horizontal line at the response related to the upper-end dose. However, when the threshold dose is uncertain as well, linear and various exponential dose-response functions can result.