ABSTRACT
Even the inbred animals maintained under well controlled animal house conditions may show some variations among the individuals in responding to a treatment in a pharmacology or toxicology study. Though majority of the individual animals respond to the treatment in a similar manner or magnitude, few of them will be too sensitive or resistant to the treatment. There are several factors that may affect the outcome of an animal experimentation, for example factors related to the experimenter. In a nutshell, even a well designed animal experimentation is bound to show some variations in the result and it is important to understand these variations for interpreting the experimental data. We shall work out an example, to make it very clear.
