The main function of the kidneys in the human body is to filter blood and remove waste products, maintaining homeostasis. The kidneys are responsible for regulating the body's fluid balance, electrolyte levels, and blood pressure. They filter out urea, creatinine, and excess minerals from the bloodstream, excreting them as urine. Additionally, the kidneys play a crucial role in acid-base balance by managing bicarbonate and hydrogen ions. Beyond filtration, kidneys also produce hormones, such as erythropoietin, which stimulates red blood cell production, and renin, which helps regulate blood pressure. Proper kidney function is critical for overall health and well-being.