The organ that filters waste from the blood in the human body is the kidney. Humans typically have two kidneys, located on either side of the spine, and they play a vital role in maintaining fluid and electrolyte balance. They filter blood to remove toxins, excess salts, and waste products, which are then excreted as urine. Additionally, kidneys are essential for regulating blood pressure, producing hormones that influence red blood cell production, and maintaining the body's acid-base balance. Healthy kidney function is crucial for overall health and well-being.