I am covering this simple and mundane acute toxicity test to increase the awareness, understanding and an appreciation of acute toxicity test, which has undergone sea-change in the last decade. In this commentary, I am not going to discuss details of different OECD guidelines which any one can download from the OECD website. The conventional acute oral toxicity test (Formerly OECD Test Guideline 401) involving treatment of multiple simultaneous dose groups of animals of both sexes which used over 40 rats, which was the most heavily criticized test in terms of animal welfare. This concern was the driving force behind the development of three alternative tests for acute oral toxicity (Test Guidelines 420, 423, 425). Anticipating the presence of validated alternatives, OECD Member countries took the initiative of deletion of OECD Guideline 401.