First Aid · Life-Threatening Emergencies
CPR, cardiac arrest, heart attack, severe bleeding, choking, stroke, anaphylaxis, asthma, poisoning, and seizures. Clear, step-by-step guidance for each — plus the critical things you should never do.
CPR & AED
Brain damage can begin within minutes when breathing and circulation stop. CPR (cardiopulmonary resuscitation) keeps oxygenated blood moving to the brain until an AED or emergency responders can restore a normal heart rhythm. Early CPR combined with early AED use dramatically improves survival rates.
This guide gives you the general framework. Because CPR technique differs significantly for adults, children, and infants — and guidelines are updated periodically by the American Heart Association — learning this from a live, hands-on course is strongly recommended. A 4-hour course will give you what reading cannot.
Confirm unresponsiveness
Tap the shoulders firmly and shout. "Are you okay?" If no response and no normal breathing, begin the sequence.
Call 911 — or direct someone to call
Be specific: point to one person and say "You — call 911 now." Simultaneously, direct someone else to find an AED.
Begin chest compressions
Place the heel of your hand on the center of the chest. Press down hard and fast — at least 2 inches deep for adults, at a rate of 100–120 compressions per minute. Allow the chest to fully recoil between compressions. Push hard. Most people don't push hard enough.
Use the AED as soon as it arrives
Turn it on and follow its voice prompts exactly. AEDs are designed to be used by untrained bystanders — the device will guide you. Minimize interruptions to compressions.
Continue until help takes over
Keep going until professional help arrives, the AED advises a different action, another trained person relieves you, the person shows clear signs of life, or the scene becomes unsafe. Performing CPR to exhaustion is not a failure — it is the whole point.
What an AED does
An AED (Automated External Defibrillator) analyzes the heart's electrical rhythm and determines whether a shock is needed. It then tells you exactly what to do — step by step, out loud. You do not need to interpret anything. You follow the voice.
AEDs are located in most public buildings: schools, gyms, libraries, airports, sports arenas, government offices. Knowing where the nearest one is before an emergency is a worthwhile three-minute investment.
Get trained
CPR certification through the American Red Cross or American Heart Association typically takes 4–8 hours and costs $50–$90. It is valid for two years. Hands-on practice builds muscle memory that no written guide can replicate — particularly the depth and rate of compressions, which most people significantly underestimate until they feel it.
Compression-only CPR (without rescue breaths) is a viable option for untrained bystanders. Dispatch operators can also guide you through CPR over the phone while help is on the way.
Heart attack & cardiac arrest
A heart attack happens when blood flow to part of the heart muscle is blocked. The heart usually keeps beating — but tissue begins to die. The person may be conscious and alert. The priority is calling 911 immediately; time is muscle.
A sudden cardiac arrest happens when the heart stops pumping effectively. The person becomes unresponsive and stops breathing normally. This requires CPR and AED immediately. A heart attack can trigger cardiac arrest.
Warning signs of heart attack — call 911 immediately
Chest pressure, squeezing, fullness, pain, or burning
Pain spreading to the shoulder, arm, back, neck, or jaw
Shortness of breath, unusual sweating, nausea
Weakness, dizziness, faintness, or unexplained fatigue
Heart attack symptoms in women
Women are more likely to experience heart attack symptoms that don't include classic chest pain. Symptoms may include unusual fatigue, dizziness, abdominal discomfort, back pain, nausea, or upper-body pain without any chest pressure at all. Do not wait for symptoms to "feel serious enough." If something feels wrong, call.
What to do
Call 911 immediately. Do not drive yourself or the person to the hospital.
Have the person sit or lie down in whatever position is most comfortable. Loosen tight clothing.
If the person is conscious and not allergic, the 911 dispatcher may advise giving aspirin. Follow dispatcher instructions.
Stay with the person. Monitor breathing and alertness. Be ready to begin CPR if they become unresponsive and stop breathing normally.
If they become unresponsive: begin CPR and use the AED as soon as it arrives.
Severe bleeding
Severe bleeding can become life-threatening within minutes. The human body contains roughly five liters of blood. The goal is simple and singular: stop the leak. Everything else is secondary until the bleeding is controlled.
The most common first-aid mistake with bleeding is checking the wound too early. Lifting the bandage to look breaks the clotting process. Do not check. Add layers and press harder if blood soaks through.
Call 911 and put on gloves
For severe or spurting bleeding, call 911 immediately. Put on latex-free gloves and eye protection before contact.
Find the source
Open or remove clothing to locate the actual wound. Treating over fabric is less effective.
Apply firm, direct pressure — with body weight
Place a clean cloth, sterile gauze, or your hand directly over the wound. Press down using your body weight — not just your fingers. Hold firm and continuous pressure for at least 5–10 minutes.
Add, don't lift
If blood soaks through the first dressing, do not remove it. Place another layer directly on top and press harder. Removing the dressing breaks the clot.
Secure with a pressure bandage if bleeding slows
Wrap the dressing firmly with a roller bandage or elastic wrap. Snug enough to maintain pressure — not so tight it cuts off circulation. Check warmth, color, and feeling beyond the bandage.
Tourniquet for life-threatening limb bleeding — with training
A commercial tourniquet (CAT or SOFTT-W) applied 2–3 inches above the wound can control bleeding that direct pressure cannot stop on a limb. Apply, note the time, and do not remove it. Tourniquets require hands-on training — the Stop the Bleed course covers this in about 90 minutes.
Monitor for shock
Significant blood loss causes shock. While controlling bleeding, watch for: restlessness, confusion, cool pale clammy skin, rapid weak pulse, extreme thirst, and fainting.
Keep the person lying down and warm. Do not give food or drink. Call 911 if you haven't already. Detailed shock guidance is in the 8-Step Method page.
The Stop the Bleed course
A 90-minute hands-on course taught at hospitals, fire stations, community centers, and workplaces across the country. Covers direct pressure technique, wound packing, and tourniquet application. Free or low-cost at most locations. Find a course at stopthebleed.org.
Choking
Choking occurs when a foreign object blocks the airway, preventing normal breathing or speaking. The key judgment to make first: is the airway partially blocked (person can still cough, speak, or breathe) or fully blocked?
A strong, effective cough generates more force to dislodge an object than back blows or abdominal thrusts. If the person can cough, encourage it. Do not interfere until the cough becomes weak or the airway becomes fully blocked.
Signs of choking to recognize
Weak or absent cough
High-pitched sounds or no sound when breathing
Inability to speak, cry, or cough effectively
Pale or bluish lips, fingernails, or skin
Hands clutching the throat — the universal choking sign
Visible panic, wide eyes, frantic movements
If the person CAN cough, speak, or breathe
Encourage them to keep coughing. Stay close and watch. Do not slap them on the back, reach into their mouth, or perform abdominal thrusts. A strong cough is the most effective intervention available. Intervene only if the cough weakens significantly or the airway becomes fully blocked.
If the person CANNOT breathe, speak, or cough effectively
Call 911 or direct someone to call immediately.
Tell the person you are going to help them. This matters — the technique startles people if unexpected.
Give 5 firm back blows between the shoulder blades with the heel of your hand, leaning them slightly forward.
Give 5 abdominal thrusts (Heimlich maneuver): stand behind the person, place a fist just above the navel, cover with your other hand, and give firm inward-and-upward thrusts.
Alternate 5 back blows and 5 abdominal thrusts until the object is dislodged or the person becomes unresponsive.
If the person becomes unresponsive: lower them carefully to the ground and begin CPR. Each time you open the airway to give breaths, look for the object — remove it only if you can clearly see it.
For infants under 1 year
The technique is different and requires specific training. Abdominal thrusts are not used for infants — the approach uses back blows and chest thrusts. If you have a child under one year in your household, include infant CPR and choking response in your next first-aid course.
Choking alone
If you are choking and alone: call 911 first if you can. Then try forceful coughing. You can attempt self-administered abdominal thrusts by making a fist above your navel and thrusting inward and upward, or by dropping sharply onto the edge of a hard surface such as a chair back or countertop.
After a choking episode
Even after an object is successfully dislodged, seek medical evaluation if the person experienced significant distress, the object was sharp, or abdominal thrusts were used (which can cause internal injury). Blunt abdominal thrusts are effective but not entirely without risk.
Stroke
Stroke occurs when blood supply to part of the brain is interrupted — either by a blockage (ischemic stroke) or a bleed (hemorrhagic stroke). Brain cells begin dying within minutes. There is no first-aid treatment that restores blood flow; the treatment happens at a hospital. Your job is to recognize the signs and get help there fast.
The time symptoms began matters enormously for treatment decisions. The moment you suspect stroke, note the time and call 911. Do not wait to see if symptoms improve.
The FAST test — use it immediately
Face
Ask the person to smile. Watch for drooping on one side of the face or mouth.
Arms
Ask the person to raise both arms. Watch for one arm drifting downward involuntarily.
Speech
Ask the person to repeat a simple sentence. Listen for slurred, strange, or absent speech.
Time
If any of the above are present, call 911 immediately. Note the exact time symptoms began.
Other sudden stroke symptoms
While waiting for help
If symptoms pass
Brief episodes of stroke-like symptoms that resolve on their own may be transient ischemic attacks (TIAs) — sometimes called mini-strokes. They are serious warning events. The person should be evaluated by a doctor that same day. Symptoms passing does not mean the emergency has passed.
Anaphylaxis
Anaphylaxis is a life-threatening whole-body allergic reaction. It can be triggered by insect stings, foods (peanuts, shellfish, tree nuts, dairy, and others), medications, latex, or other allergens — sometimes in people with no prior history of severe reactions.
Epinephrine is the primary treatment. Antihistamines like diphenhydramine are not a substitute — they work too slowly for anaphylaxis and do not treat airway swelling. If an epinephrine auto-injector is available and prescribed, use it immediately. Then call 911 regardless of whether symptoms improve.
Warning signs
Trouble breathing, wheezing, or stridor
Swelling of the tongue, lips, throat, or face
Widespread hives or rash appearing suddenly
Tightness in the throat or chest
Vomiting, stomach cramps, or severe nausea
Dizziness, fainting, confusion, or collapse
Call 911 immediately. Anaphylaxis requires emergency medical care even if symptoms improve after epinephrine — reactions can return.
Use the epinephrine auto-injector if the person has one prescribed. Help them use it if they are unable — most devices have clear instructions on the label. The outer thigh is the standard injection site, through clothing if needed.
Position appropriately. If breathing is difficult, sit the person upright. If they feel faint, have them lie down with legs elevated. If unconscious and breathing, use the recovery position.
A second dose may be needed if symptoms continue or return and a second auto-injector is available. Note the time of each injection for emergency responders. Stay with the person until help arrives.
Antihistamines are not the answer
Diphenhydramine (Benadryl) and similar antihistamines work too slowly and do not address airway swelling or circulatory collapse — the two mechanisms most likely to be fatal in anaphylaxis. They may have a role as a secondary treatment after epinephrine, but they are never a substitute for it.
If epinephrine is not available and 911 has been called, keep the person as calm and still as possible. There is no OTC substitute for epinephrine.
If you have a known severe allergy
Asthma emergencies
In an asthma attack, the airways narrow and swell, making breathing difficult. Most people with asthma carry a prescribed rescue inhaler (commonly albuterol). The first job of a bystander is to help them get to that inhaler and use it — the medication they've been prescribed is the right treatment.
Your role is support, not substitution. Do not give someone else's inhaler or any other medication. Your job is to keep the person calm, help them sit upright, and assist them in using their own prescribed device according to their doctor's instructions.
Help the person sit upright — this position eases breathing effort
Help them locate and use their rescue inhaler if they are struggling to do so alone
Keep the environment as calm as possible — anxiety worsens airway constriction
Remove from smoke, dust, or any obvious trigger if possible
Call 911 if the person does not have their inhaler, if the inhaler is not helping after a reasonable attempt, if their lips or fingernails turn blue, or if they are too exhausted to speak in full sentences
For households with an asthmatic member
Asthma attacks can escalate quickly. Make sure every adult in the household knows: where the rescue inhaler is kept, what the person's prescribed steps are for an attack, and at what point to call 911.
Many people with asthma have a written asthma action plan from their doctor that specifies exactly when to use the rescue inhaler, when to take additional steps, and when to call for help. Ask if one exists and know where it is.
Triggers vary widely — dust, exercise, cold air, smoke, mold, animal dander, stress. Knowing the person's specific triggers helps reduce the frequency of attacks and speeds the response when one occurs.
Poisoning
Poisons can be swallowed, inhaled, absorbed through the skin, splashed into the eyes, injected, or taken in overdose. The correct response depends entirely on the type of exposure — which is why Poison Help exists. A trained specialist will walk you through exactly what to do.
Do not make the person vomit unless specifically directed by Poison Help or 911. For many substances, inducing vomiting causes additional damage.
911
Call if: collapsed, seizing, trouble breathing, or cannot be awakened
1-800-222-1222
Poison Help — 24/7, all other poisoning situations
Swallowed poison
Inhaled poison
Poison on skin or in eyes
Wild plants and mushrooms
"Natural" does not mean "safe." Many toxic plants look similar to edible ones, and many dangerous mushrooms closely resemble edible varieties. Do not eat wild plants, berries, or mushrooms unless you are certain of their identity through proper training — not app identification. If ingestion is suspected, call Poison Help immediately with as much description of the plant or mushroom as possible.
What to tell Poison Help
Medication overdose
Accidental overdose on prescription or OTC medications — including acetaminophen — is a common poisoning scenario. Call Poison Help immediately. Do not wait for symptoms to appear; some overdoses cause no immediate symptoms but damage organs over hours.
If the person is unresponsive or not breathing normally, call 911. If opioid overdose is suspected and naloxone is available, follow the instructions on the device.
Seizures
A seizure is caused by sudden, uncontrolled electrical activity in the brain. It may look alarming — the person may lose consciousness, fall, stiffen, or have rhythmic jerking movements. Most seizures end on their own within 1–3 minutes.
The most important things a bystander can do are simple: protect the person from injury, time the seizure, and stay with them. The most important things not to do are equally simple — and widely misunderstood.
What TO do
What NOT to do
When to call 911
The seizure lasts more than 5 minutes
This is the person's first known seizure
The person does not regain consciousness after the seizure
A second seizure follows shortly after the first
The person is injured during the seizure
The person is pregnant or diabetic
The seizure occurs in water
You are unsure whether the person has breathing difficulty
After the seizure
After a seizure ends, the person typically enters a postictal period — a period of confusion, disorientation, exhaustion, and sometimes distress that can last from minutes to hours. This is normal and not a cause for additional alarm.
For households with a known epileptic
People with epilepsy often have a seizure action plan from their neurologist that specifies when bystanders should call 911 and when observation is sufficient. Ask if one exists and know where it is.
Some individuals with epilepsy have rescue medications (such as diazepam or midazolam nasal spray) prescribed for prolonged seizures. Know where these are and how to use them before you need to.
Continue reading
Next in the guide
Cuts, scrapes, puncture wounds, embedded objects, splinters, fishhooks, and the infection signs that tell you a wound needs more than a bandage.
Wound care guideOr go back
Stabilize the scene before treating the injury. The universal framework behind every situation on this page.
Method guide