The object of toxicological testing is to predict possible adverse effect in humans when exposed to chemicals whether used as industrial chemicals, pharmaceuticals or pesticides. Animal models are predominantly used in identifying potential hazards of chemicals. The use of laboratory animals raises ethical concern. However, irrespective of animal welfare it is an important aspect of the discipline of toxicology that the primary object is human health. The ideal testing and assessment strategy is simple to use all the available test methods and preferably more in laboratory animal species from which we get as many data as possible in order to obtain the most extensive database for the toxicological evaluation of a chemical. Consequently, the society has decided that certain group of chemicals should be tested accordingly. However, realising that, this idea is not obtainable in practice because there are more than 100000 chemicals which are potential for human exposure, so the development of alternative testing and assessment strategies has taken place in the recent years. The toxicological evaluation should enable the society to cope with the simultaneous requirement of many chemicals for different uses and of the absence of health problems involved with their use. Thus, the regulatory toxicology is a cocktail of science and pragmatism added a crucial concern for animal welfare. Test methods are most often used in a testing sequence as bricks in a testing strategy. The main key driving forces for introducing assessment and testing strategies e.g. using a limited number of tests and/or alternative test methods are: (a) animal welfare considerations; (b) new scientific knowledge i.e. introducing tests for new endpoints and tests for better understanding of mode of action; and (c) lack of testing capacity/reduction of required resources economically as well as time wise.