The term for filtering out harmful substances from fluid in the body is excretion. This physiological process primarily occurs in the kidneys, which filter blood to remove waste products, excess ions, and metabolic byproducts, forming urine. Additionally, other organs like the liver and lungs play roles in detoxifying and excreting substances. Efficient excretion is vital for maintaining homeostasis and preventing the accumulation of toxins that can disrupt bodily functions. Studying excretion informs medical research, highlighting mechanisms of disease and treatment strategies.