The present study paper on the biological assays of pharmaceutical product is intended to review on the available literature that are widely applicable in the bioassay of pharmaceutical substances. There is an urgent need for more strategies and procedures for bioassay techniques, including methods that employ multicellular and unicellular organism. The presence of small amounts of pyrogen or endotoxin in recombinant protein preparations and other pharmaceutical product can cause side effects in host organism such as endotoxin shock, tissue injury, and even death. Due to these reactions, it is essential to remove endotoxins from drugs, injectables, and other biotechnological products, an overview of this subject is provided by this paper. An extensive review of literature with regard to methods for pyrogen, endotoxin and toxicity bioassay test of pharmaceutical and biotechnological preparation was carried out. Rabbit pyrogen test is an older, more routine, standard and official in-vivo multicellular test methods in most pharmaceutical compendia. Limulus amebocyte lysate (LAL) is an in-vitro test currently employ in the detection and quantification of endotoxins that are of bacteria and non bacterial origin in a variety of solution, and can be use for screening of starting materials. The possible advantages of LAL test compared to Rabbit method include rapidity, reliability, ease and adaptability. Biological assays are very essential in clinical medicine and other field of science for the role it plays in evaluation and assessment of pharmaceutical and biotechnological preparation.