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The history of bioassay goes back many hundred years. One of the more unusual applications is that numerous rulers had cupbearers who tried the ruler’s food and drank to avoid poisoning and probably the demise of the regent. The bioassay response was the survival/health of the cupbearer.

“What is  not poisonous: Everything is a poison and nothing is inert. The dose alone decides whether a thing is a poison or not.”

Paracelsus (1494-1541) 

In a nutshell

Dose: Concentrations of a chemical (Root length inhibitor) that might evoke a reaction in living organisms (root length inhibitor) 

Response: Biological reaction (Root length growth), also called: endpoint or outcome or y, at a given dose. 

Like the one in Figure 1, Dose-response analysis can be carried out using multi-purpose commercial statistical software. Still, except for a few special cases, the analysis easily becomes cumbersome as relevant, non-standard output requires manual programming.  

The extension package drc for the statistical environment R (r-projekt) provides a flexible and versatile infrastructure for dose-response analyses in general.  

This homepage aims to provide an overview of state-of-the-art dose-response analysis, both in terms of general concepts evolved and matured over the years and through concrete examples. 

Jens Carl Streibig

Professor Emeritus of Weed Science at the Faculty Science, University of Copenhagen, Denmark

Christian Ritz

Professor, Statens Institut for Folkesundhed Professor, Forskningsafdelingen for Sundhed og sygelighed i befolkningen