A hand on a chest giving CPR during a medical emergency.

When you witness a medical emergency—in your own home or out in public—what can you do to help? Calling 911 is a great place to start, but in many cases even an untrained bystander can provide care that may help save a life.

“It’s important to know that you can do something even if you’re not trained in how to handle the emergency,” says Jeffrey L. Pellegrino, Ph.D., professor of health sciences at Aultman College in Canton, Ohio. It’s equally important to know that Good Samaritan laws in all states protect you from being sued if you act in good faith to help someone out.

To help you do the right thing (and avoid doing something that may cause more harm) in a variety of emergency scenarios, the following cheat sheet gives some basic advice from emergency-medicine experts.

Fainting

If you’re with someone who suddenly feels lightheaded and might faint (or if you feel that way yourself), there are two things you can do.

More on Medical Emergencies

“First, get them lying down—not just sitting but fully horizontal,” says Eunice Singletary, M.D., a member of the American Red Cross Advisory Council. “Otherwise, they are at risk of falling, which could lead to a head injury or broken arm.”

The other thing to try is a technique called “physical counter pressure maneuver.” If someone feels like he may faint or has already fainted, have him squeeze your hand or their own hands together very tightly, or instruct him to cross his legs and squeeze his thighs.

“It helps push the blood back into the head, raising the blood pressure and resolving the symptom of feeling lightheaded,” Singletary says. 

Seizure

You can’t stop someone from seizing—and you could get yourself injured if you try. But you can help her stay safe by getting her to the floor and surrounding her with pillows or other padding.

“The force of a seizure can be tremendous,” says Latha Ganti, M.D., professor of emergency medicine and neurology at the University of Central Florida College of Medicine, “so it’s important to protect their head.”

Once the seizure has ended, flip the person onto her side. “This is called the recovery position,” Singletary says.

After a seizure, a person’s tongue can get limp and fall back into her airway if she’s lying on her back. Turning her on her side helps her to breathe better.  

Bleeding

If someone cuts themselves badly, the first things you want to do are find out exactly where the blood is coming from and assess how badly the cut is bleeding.

“You may have to remove clothing if there’s a lot of blood in order to see the source of the bleeding,” Ganti says.

It’s no longer recommended that you elevate the bleeding limb. It’s more important to put strong, direct pressure on the wound (which is hard to do if it’s raised). If possible, put the area that’s bleeding on a hard surface and use the palm of your hand to apply heavy, direct pressure to the wound.

If you’re concerned about infection (and don’t have gloves handy), Singletary recommends placing a plastic bag or layer of plastic wrap between your hand and the cut.

If direct pressure does not help stem the flow of blood, the injury may require a tourniquet. You need to place it 2 inches above the bleeding and tighten it until it compresses the artery and stops the bleeding.

“If you don’t have a first-aid kit with a tourniquet, you can improvise,” Ganti says. “A leather belt, a scarf, a bungee cord—anything you can wrap around the limb and tighten.”  

Stroke

The general rule for stroke is that “time is brain tissue”—meaning that the most important thing a bystander can do is to recognize that someone is having a stroke and get him emergency help as quickly as possible.

Use the acronym FAST to assess someone for a possible stroke. “F” is for facial drooping, “A” for arm weakness, “S” for slurred speech or difficulty speaking—any one of those means “T”: It’s time to call 911.

You can also help speed the time it takes first responders to take appropriate action by letting the 911 dispatcher know you’ve done FAST and suspect a stroke.

“Also, if the person has any medications with them—or you’re in their home—gather those to give to the EMTs when they arrive,” Ganti says. “Knowing what medications they take can help the first responders determine more quickly if the patient is eligible for certain therapies.”  

Heart Attack

If someone is having chest pains or other symptoms of a heart attack (e.g., jaw pain, shortness of breath, nausea), the first thing is to tell her to sit down. “Don’t let them move around, because the slightest exertion could make it worse,” Singletary says.

Then, if there’s aspirin available, give her a full 325-mg dose (or four tablets of low-dose aspirin) and have her chew it. “If you swallow whole pills it takes 12 minutes before it’s absorbed and starts helping, but if you chew the pills, it only takes 4 minutes,” she says.  

Cardiac Arrest

If someone’s heart has stopped beating, you need to start CPR immediately. Our experts suggest starting CPR whenever someone is unconscious and unresponsive because untrained people don’t always take pulses correctly and looking for one can waste critical time.

“Don’t worry about the breathing, just start doing good chest compressions, 2 inches deep, 100 per minute,” Ganti says. In most cases, this approach, called hands-only CPR, has been shown to be just as effective as traditional CPR with resuscitation breaths—and it’s much easier. (For a complete guide to this type of CPR, see our previous coverage here.)

If there is an automatic external defibrillator on-site, have someone else go get it, read the instructions, and apply the pads while you continue compressions.

“Don’t be afraid to use the AED,” Pellegrino says. “The machines are smart, and the instructions are very self-explanatory.” Once the pads are placed, the machine will let you know what to do, announcing either “Stand clear, stop CPR” or “No shock advised, continue CPR.”  

How to Make Sure You're Prepared

Being well-trained and well-equipped can make you better able to take charge of an emergency while waiting for an ambulance to arrive.

A few things you can do:

  • Always have your cell phone handy. Put your phone on speaker and call 911 immediately. Then leave the phone nearby so that you can continue to communicate with the dispatcher until help arrives. “The dispatchers go through a lot of training and can successfully coach you through what to do in a variety of emergency situations,” Pellegrino says.
  • Keep a well-stocked first-aid kit. Have one in your home, your car, the bag you take to the kids’ sports practices, etc. The more supplies you have on hand, the more easily you’ll be able to help.
  • Download a first-aid app. The Red Cross First Aid app is available free in app stores. It includes step-by-step instructions and videos on how to handle a variety of medical emergencies.
  • Take a class. You can learn CPR and basic first-aid techniques by taking an online or in-person course offered by the Red Cross or another organization.  

Clarification: The section on fainting has been updated to clarify that the person who feels like fainting should try squeezing his or her own hands or legs together; a bystander cannot squeeze the person's hands for him or her.