Division 1.3 PRINCIPLE OF THE TEST

It is the principle of the test that, based on a stepwise procedure with the use of a minimum number of animals per step, sufficient information is obtained on the acute toxicity of the test substance to enable its classification. The substance is administered orally to a group of experimental animals at one of the defined doses. The substance is tested using a stepwise procedure, each step using three animals of a single sex (normally females). Absence or presence of compound-related mortality of the animals dosed at one step will determine the next step, i.e.;

• no further testing is needed,

• dosing of three additional animals, with the same dose

• dosing of three additional animals at the next higher or the next lower dose level.

Details of the test procedure are described in Annex 1. The method will enable a judgement with respect to classifying the test substance to one of a series of toxicity classes defined by fixed LD₅₀ cut-off values.