Diabetic Emergencies: What Bystanders Can Do
When blood sugar swings dangerously, a calm bystander who knows the sugar-first rule can prevent a tragedy.
If someone with diabetes is acting unwell and you’re unsure whether their sugar is high or low, treat for low and give sugar (only if they can swallow safely). Give 15–20 g of fast-acting sugar — 3–4 glucose tablets, 50–100 ml of juice or regular soda, or a tablespoon of sugar. Wait ~15 minutes, then repeat once if they’re not improving (the “Rule of 15”). Never give insulin, and never put anything in the mouth of someone unconscious or unable to swallow — call 911, place them in the recovery position, and use a glucagon kit only if you’re trained.
Diabetes is one of the most common chronic conditions in Canada — Diabetes Canada estimates that more than three million people are living with diagnosed diabetes — which means a diabetic emergency can happen anywhere: at work, on the bus, in a restaurant, or at a family dinner. The good news is that the most dangerous of these emergencies, a sudden drop in blood sugar, is also one of the easiest for a bystander to treat. You do not need a medical background. You need to recognize the signs and remember one simple rule.
Prevalence estimate: Diabetes Canada.
Source: Canadian Red Cross (first aid for diabetic emergencies) — “when in doubt, give sugar.”
Two Kinds of Diabetic Emergency
Blood sugar that is too low or too high can both become emergencies, but they look and behave very differently.
Low blood sugar (hypoglycemia) — the fast, dangerous one
This happens when blood sugar drops too low, often because a person took too much insulin, skipped a meal, drank alcohol, or exercised more than usual. It comes on quickly — within minutes — and is the more immediately life-threatening of the two. Untreated, it can lead to unconsciousness, seizures, and death.
High blood sugar (hyperglycemia) — the slow one
This develops gradually over hours or days, often during illness or when insulin doses are missed. It is serious and can progress to a dangerous condition called diabetic ketoacidosis, but it rarely requires the same split-second response as a low.
Recognizing Low Blood Sugar
Low blood sugar tends to come on suddenly. Watch for:
- Shakiness and trembling
- Sweating and pale, clammy skin
- Sudden intense hunger
- Confusion, irritability, or unusual behaviour — sometimes mistaken for drunkenness
- Dizziness or weakness
- A fast or pounding heartbeat
- Slurred speech and poor coordination
- Drowsiness, and if untreated, unconsciousness or seizures
Recognizing High Blood Sugar
High blood sugar builds slowly. Signs include:
- Extreme thirst and a very dry mouth
- Frequent urination
- Tiredness, weakness, or drowsiness
- Warm, dry skin
- Fruity or acetone-smelling breath (like nail polish remover)
- Deep, rapid breathing
- Nausea, vomiting, or abdominal pain
If you see these signs — especially fruity breath and rapid breathing — the person needs medical help. Call 911.
Step-by-Step: Helping Someone With Low Blood Sugar
1Check that they are conscious and can swallow
Only give food or drink if the person is fully awake and able to swallow safely. If they are drowsy, confused to the point of being unable to cooperate, or unconscious, skip to the unconscious instructions below.
2Give 15–20 grams of fast-acting sugar (the “Rule of 15”)
Glucose or dextrose tablets are the preferred choice — 3 to 4 tablets give about 15–20 g. If tablets aren’t available, use 50–100 ml of fruit juice or regular non-diet soda, a tablespoon of table sugar or honey, or several hard candies. Avoid chocolate or anything with fat — the fat slows sugar absorption when you need it fast.
Source: ILCOR (glucose tablets preferred; dietary sugars if unavailable); ERC 2025 first aid (15–20 g dose; 50–100 ml juice/soda). Aligned with Canadian Red Cross / Heart & Stroke.
3Wait about 15 minutes, then reassess
Sit with them and give the sugar time to work. After about 15 minutes, check whether they feel better. If they are still unwell or not improving, give another 15–20 grams of fast-acting sugar.
Source: ERC 2025 first aid — repeat oral glucose after ~15 minutes if symptoms persist.
4Follow up with a longer-lasting snack
Once they have improved, offer a snack with longer-lasting carbohydrates — crackers, a sandwich, fruit, or a granola bar — to keep their blood sugar stable, especially if their next meal is more than an hour away.
5If they do not improve, call 911
If two doses of sugar have not helped, or the person is getting worse rather than better, call 911. Keep monitoring them closely while you wait.
If the Person Is Unconscious or Seizing
- Call 911 immediately.
- Place them in the recovery position (on their side) so the airway stays clear.
- If they have a prescribed glucagon kit and you have been trained to use it, follow that training. Otherwise, wait for paramedics.
- If they stop breathing normally and are unresponsive, begin CPR and continue until help arrives.
Source: ILCOR / ERC 2025 first aid — no oral sugar if unresponsive (aspiration risk); glucagon only if prescribed. Canadian Red Cross recovery-position and CPR guidance.
When to Call 911
Call 911 for a diabetic emergency if the person:
- Is unconscious or cannot swallow
- Is having a seizure
- Does not improve after two doses of sugar
- Is drowsy and getting worse
- Is vomiting and cannot keep fluids down
- Has fast, deep breathing with fruity-smelling breath (a sign of high blood sugar emergency)
- Or whenever you are simply unsure what is happening
What NOT to Do
- Do not give insulin. As a bystander, never administer someone else’s insulin — insulin drives sugar out of the blood, so if their sugar is already low, it could be fatal.
- Do not give food or drink to an unconscious person.
- Do not assume someone confused or stumbling is drunk. Consider low blood sugar.
- Do not leave the person alone until they have fully recovered or help has arrived.
Source: Canadian Red Cross / ILCOR — a bystander never gives insulin; glucose is the safe choice.
Learn the Hands-On Skills
Recognizing a diabetic emergency is the first step, but the response can quickly involve the recovery position, airway management, and even CPR. These are skills best learned by practising them. A Life Safe first aid course covers diabetic emergencies alongside the practical, hands-on skills that let you act confidently when someone’s blood sugar crashes in front of you.
Frequently Asked Questions
What are the signs of low blood sugar?
Low blood sugar comes on quickly: shakiness, sweating, paleness, sudden hunger, irritability or confusion, dizziness, a fast heartbeat, and slurred speech — sometimes looking like drunkenness. Untreated it can lead to unconsciousness and seizures. If unsure whether sugar is high or low, treat for low by giving sugar (Canadian Red Cross).
What should I give someone with low blood sugar?
If they are awake and can swallow, give 15–20 grams of fast-acting sugar (the Rule of 15): 3–4 glucose tablets, 50–100 ml of juice or regular soda, a tablespoon of sugar or honey, or several hard candies. Wait about 15 minutes, then give another 15–20 grams if needed. Follow with a longer-lasting snack. Never give anything by mouth to someone unconscious. Aligned with ILCOR / ERC 2025.
When should I call 911 for a diabetic emergency?
Call 911 if the person is unconscious or cannot swallow, is having a seizure, does not improve after two doses of sugar, is drowsy and worsening, is vomiting, or has fast deep breathing with fruity-smelling breath. Also call if you are simply unsure — these emergencies can deteriorate quickly.
What is the difference between low and high blood sugar?
Low blood sugar comes on fast — minutes — with shakiness, sweating, and confusion, and risks rapid collapse. High blood sugar develops over hours or days with extreme thirst, frequent urination, fatigue, and fruity breath. Low sugar is the more immediate emergency. When in doubt, give sugar.
Should I give insulin to someone having a diabetic emergency?
No. Never administer someone else’s insulin as a bystander — if their sugar is already low it could be fatal. Give 15–20 g of fast-acting sugar if they are conscious and can swallow, place them in the recovery position if unconscious, call 911, and let paramedics manage insulin and glucose.
Would You Know What to Do?
Diabetic emergencies happen in everyday places, often in front of people who freeze because they are unsure. Life Safe’s hands-on first aid courses teach you to recognize and respond to medical emergencies — diabetes, seizures, cardiac arrest, and more — with calm and confidence.
Find a class near you: Toronto • Downtown Toronto • East York • Hamilton • Welland • Guelph
Sources & medical review
Reviewed by Milos Radojcic (Canadian Red Cross / Heart & Stroke / Lifesaving Society First Aid & CPR Instructor, 10+ yrs). Clinical content aligned with the Canadian Red Cross, the Heart & Stroke Foundation of Canada, and the 2025 ILCOR consensus, with hypoglycemia dosing per the ERC 2025 first aid guidelines (15–20 g fast sugar; 50–100 ml juice/soda; repeat after ~15 min). Diabetes prevalence per Diabetes Canada. Last reviewed July 2026.