Islam has made some rules about the animals that among them, the quadrupeds which are originally and naturally halal-meat, have some parts that are not permissible to be consumed even after religious purification. Considering its relation to human's nutrition, it is necessary to pay attention and study these rules. The development of animals science in the current era has raised so many questions about the relationship and consistency and inconsistency of the scientific findings with these rules. using descriptive-analytical research method, the present study aims at describing the reason of unlawfulness of some parts from Jaʽfari jurisprudence's viewpoint and then comparing them with the existing scientific findings. In this study, it was concluded that some of these components serve as sites for the accumulation of microbes and excretory factors of quadrupeds, which are often pathogenic to humans and have no specific nutritional value. Furthermore, due to the risk of transmitting zoonotic diseases, causing digestive problems, and various other health-related issues, their consumption has been prohibited in order to avoid physical harm. However, this prohibition is not because these organs are bad or impure, but simply because they are unsuitable and prohibited for human consumption.