The first thing you should do when someone falls unconscious is to call 911 and explain the situation to the dispatcher. After that, you should continue to monitor their condition to see if their pulse or breathing stops, beginning CPR if necessary, according to the National Institutes of Health.
If you think the unconscious individual has a spinal injury, do not move them as long as they continue to breathe, instructs the National Institutes of Health. If the person vomits, roll him to the side while keeping his neck and back supported so he stays in the same position while turning. If you don't think the person has a spinal injury, roll him toward you on his side and bend the top leg so that the hip and knee are both at right angles. Then, tilt the head back to keep the airway open.
Do not give an unconscious person food or drink, as he cannot swallow it. Never leave the individual alone, as he could stop breathing or go into cardiac arrest and need assistance. Refrain from putting a pillow under the unconscious person's head, according to the National Institutes of Health. Finally, do not slap or splash water on an unconscious person's face.