→ Lungs: Lungs remove large quantities of carbon dioxide (18 L /day) and significant quantities of water.
→ Liver: The liver secretes bile which contains bilirubin, biliverdin, cholesterol, steroid hormones, vitamins and drugs. These are excreted out along with the digestive wastes.
→ Skin: Sweat glands eliminate certain wastes like urea and lactate. Sebaceous glands eliminate sterols, hydrocarbons, and waxes through the serum.
→ Saliva: Small quantities of nitrogenous wastes are excreted through saliva.