Fetal Bovine Serum (FBS) is a nutrient-rich liquid derived from the blood of bovine fetuses, typically collected during the slaughter of pregnant cows. It is widely used in cell culture and laboratory research because it provides essential growth factors, hormones, and nutrients that support the growth and maintenance of various cell types. FBS is often used in the production of vaccines, pharmaceuticals, and in vitro fertilization. Its ability to promote cell proliferation makes it a valuable component in many biological experiments, although ethical concerns regarding animal welfare and sourcing practices have led to ongoing discussions about alternatives.