First aid is the immediate care provided to an injured or ill person until full medical treatment is available. It aims to preserve life, prevent further harm, and promote recovery. The document provides guidance on how to treat common injuries and medical emergencies such as bleeding, burns, bites, broken bones, choking, fainting, and seizures through first aid techniques like applying pressure, administering CPR, and positioning the body. Proper first aid is crucial for stabilizing a person's condition until emergency medical services arrive.