There's no substitute for a medical professional, but if you're first on the scene, some basic knowledge can help you save the day.

Credit: Jasu Hu

It would be nice to think that in a health emergency—a man at the next table starts choking on his sushi, a woman in the elevator goes into labor—you’d swoop in like a superhero, giving aid until the EMTs arrive. But your first reaction may actually be, “I was an English/music/accounting major! What do I know about medicine?”

“Anyone can step in and help out. You just need the willingness and confidence to do it,” says Jonathan Epstein, a paramedic and the senior director of science, industry, and government relations for American Red Cross Training Services. Many people are hesitant to help, Epstein points out, because they’re afraid of being sued or of accidentally doing something to make the situation worse. “Good Samaritan laws in all 50 states help protect you even if you make a simple mistake, as long as you’re acting with good intentions,” he says.

At the very least, call 911 immediately and make sure the person is in a safe position. With some extra knowledge, you can make a big difference, and in many cases even save a life. Here’s what to know in six emergency situations so you can take confident action.

1. How to treat a burn

Most burns that happen in the home result from mundane situations (you forgot to put on an oven mitt before grabbing that pan of lasagna), and you can treat them yourself. But depending on the severity and size, some burns need immediate medical care.

Assess the severity of the burn. If the area is red and painful but there’s no broken skin or blistering, it’s a superficial (or first-degree) burn and can be treated at home. If there are blisters or broken skin, it’s most likely a partial-thickness (second-degree) burn. This type can sometimes be treated at home, “but if there’s a large blister or the burn is on the hands, face, or throat, get medical treatment right away,” says Epstein. The most serious type of burn is a full-thickness (third-degree) burn, which can appear white and waxy or black and charred. “The center of this burn won’t hurt, because you’ve burned away all the nerve endings,” explains Epstein. “However, the outer edges, which will have first- or second-degree burns, can be very painful.” If you get one of these, call 911 or go to an emergency room immediately.

Stop the burning process by holding the wound under cold, running water for 10 minutes, says Epstein. “If you’re outdoors and there’s no running water, you can pour cool water onto a clean cloth and hold that to the burn,” he says. Do not place ice directly on the burn, as it can freeze and damage the skin cells.

Once the burn has cooled off, cover it loosely with clean gauze. (Skip adhesive bandages, which can stick to the damaged skin.) Do not pop any blisters—the skin underneath needs to heal to prevent infection.

Keep it moist. Applying antibiotic ointment or petroleum jelly will feel good and help with healing. Steer clear of home remedies like butter or toothpaste, despite what your grandmother may have told you.

2. How to save someone who’s overdosed on opioids

Every day, about 130 Americans die from opioids, which include prescription painkillers and street drugs like heroin and fentanyl. Thankfully, naloxone—the opioid-overdose reversal drug—is now widely available, is covered by most insurance plans, and can even be bought at many drugstores out of pocket without a prescription, says Patricia Aussem, director of clinical content at the Center on Addiction in New York City. If you live in an area with an opioid problem or know someone struggling with addiction, keep a dose on hand and follow these steps.

Identify the signs. If someone is barely breathing and has blue lips and fingertips, rub your fist hard under their nose or along their breastbone, says Aussem. If there’s no reaction—and especially if there’s labored breathing, choking sounds, and a slow or absent pulse—call 911 ASAP. If you must step away for a moment, roll the person onto their side, put their head on their arm, and bend their top knee. This helps prevent them from choking if they vomit.

Administer naloxone. One formulation, Narcan, is a nasal spray: Hold the device in the person’s nostril and press the plunger. Evzio is like an EpiPen: Pull off the seal, place it on the thigh, press down, and hold for five seconds.

Get more help. The benefits of naloxone last from 30 to 90 minutes, so the person can stop breathing again once the naloxone wears off, without further aid.

3. How to save someone who’s choking

Always ask, “are you choking?” If the person can speak or cough, encourage them to keep trying to cough up the obstruction. If they are making high-pitched noises, coughing weakly, or unable to speak or cry, have someone call 911 while you jump into action.

Start with back blows. Stand to the side of and slightly behind the person. (If it’s a child, kneel.) Place an arm across their chest for support, bend them over at the waist, and firmly hit between the shoulder blades with the heel of your hand five times.

Then try abdominal thrusts. Stand behind the person with one foot in front of the other. If possible, place your front foot between their feet. Wrap your arms around their waist. Put one fist just above the belly button, grab your fist with your other hand, and thrust in and up strongly five times. (If the person is pregnant or too large to reach around, give chest thrusts against the center of the breastbone.) Switch between five thrusts and five back blows until the person can cough forcefully, speak, cry, or breathe, or if they become unresponsive.

If you’re choking and alone, dial 911 or use the emergency call button on your phone. “The EMTs will find you even if you can’t speak,” says Epstein. You can lean over the back of a chair and use it to give yourself abdominal or chest thrusts.

4. How to help a friend facing a mental health crisis

If a friend has withdrawn socially (from everyone, not just you); is showing signs of self-neglect (skipping showers, dressing in dirty clothes, gaining or losing a lot of weight quickly); seems irritated or angry, even about minor things; or has suddenly started leaving unusual posts on social media, they may be in a mental health crisis, says Elena Mikalsen, PhD, chief of psychology at the Children’s Hospital of San Antonio. Here’s how to help:

Try to get them out of the house. “Call and say, “I miss you. I’m going to pick you up so we can get coffee or take a walk,“” says Mikalsen. “A rut of staying in bed and not exercising or socializing can lead to a downward spiral.”

Keep it simple. Don’t drag them to a party. A one-on-one somewhere you can sit quietly and talk is best.

Don’t try to fix the depression. “The best thing you can do is just listen and be empathetic,” says Mikalsen. If applicable, mention a time when you needed help: “A couple of years ago, I was totally overwhelmed, and talking to a therapist really helped.”

Offer to help with to-dos. “When you’re depressed, you don’t feel like you can handle anything in your life,” says Mikalsen. “Ask, ‘Can I help run errands for you? What’s the most overwhelming thing you have to do today?’” You can even ask, “Can I help you find a therapist who takes your insurance?”

Watch out for suicidal thoughts. If your friend states, online or verbally, that they’re thinking of ending their life or expresses anything similarly alarming, offer to take them to the ER or a mental health clinic, or tell someone they live with.

5. How to recognize a stroke

If a friend, coworker, or parent suddenly starts acting or speaking oddly—their face droops, their speech is slurred—get help right away. They may be having a stroke, and the faster you get them to the hospital for proper treatment, the better their chance of a full recovery. “The clock starts ticking the moment the symptoms appear,” says Stacey Rosen, MD, a cardiologist and volunteer medical expert for the American Heart Association’s Go Red for Women movement. She recommends keeping in mind the tips in the acronym FAST (facial drooping, arm weakness, speech difficulty, time to call 911):

Facial drooping, tingling, or numbness: “Ask the person to try to smile at you. Or if you’re alone and think you’re having a stroke, smile in the mirror,” says Rosen. If the smile is lopsided, that’s cause for concern.

Arm weakness: “Many of my patients tell me they dropped a pen or were holding a utensil and it suddenly felt very strange,” says Rosen.

Speech difficulty: A stroke interrupts the flow of oxygen to the brain, which can make communication difficult. Speech might be garbled, or the person may not be able to form or repeat a simple sentence.

Time to call 911: When you get to the ER, don’t worry about bothering anyone with a potential false alarm. “This is not the time to be a good girl and let someone else go first,” says Rosen. “You need to scream to everyone who’s listening, ‘I think I’m having a stroke!’”

Know other symptoms too. “The symptoms can be more subtle in women than in men, but most women have an amazing sense that something is just not right,” says Rosen. Pay close attention to unusual symptoms, like sudden nausea and vomiting; an unexplained, debilitating headache; blurred vision; dizziness or trouble balancing; pain or pressure on one side of the body; or even hiccups that won’t go away.

6. How to catch a baby who’s coming out fast

Unexpected births are rare but can happen. These deliveries can usually be handled by a friend, family member, or bystander, says Sharon L. Ryan, director of midwifery practice, education, and global outreach at the American College of Nurse-Midwives. Call 911, but if the baby is faster than the EMTs, wash your hands, find clean towels or blankets for the little one to land on, and then:

Remain calm. “The calmer the mother is, the smoother the birth will be,” says Ryan. Have her lie on her side, which will help slow the baby’s descent, and encourage her to take quick, panting breaths for as long as possible, rather than bearing down.

When the baby starts crowning, simply support the baby’s head and body as it comes out, says Ryan.

Once the baby is out, gently wipe the nose and face with something clean. Place the baby naked on the mom’s bare chest, then cover both with a blanket.

Don’t cut the cord! The experts should do it safely, with sterile tools.

Learn to save a life in one day

You’ve seen those red AED (automated external defibrillator) boxes everywhere, but would you know how to use it if someone went into cardiac arrest? Grab a friend and sign up for a Red Cross class to learn how. In one five-hour session, you can get certified in adult and child CPR and AED (if you’re short on time, you can take part of the class online). While you’re at it, download the free Red Cross First Aid app for expert advice on treating everything from a broken arm to a jellyfish sting.