Endotoxins are toxic substances found in the outer membrane of certain bacteria, particularly Gram-negative bacteria. They are composed of lipopolysaccharides and can trigger strong immune responses in humans and animals. When these bacteria die and break apart, endotoxins are released into the surrounding environment, potentially leading to fever, inflammation, and other serious health issues. The presence of endotoxins is a significant concern in medical settings, especially in the production of pharmaceuticals and medical devices. Contamination can result in severe reactions, making it essential to monitor and control endotoxin levels to ensure safety and efficacy in treatments and products.