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Quick guide · 3 min read

Diabetic Emergency: Low Blood Sugar and What to Do

A hypo (low blood sugar) comes on fast: pale, sweaty, shaky, confused, sometimes aggressive. If they can swallow safely, give fast-acting sugar, then something more substantial. Unresponsive: nothing by mouth, recovery position, 999.

Spot a hypo (low blood sugar)

  • Comes on quickly, often in a known diabetic who has missed food, taken insulin, or exercised hard
  • Pale, cold, sweaty and shaky
  • Confused, irritable, slurring words, sometimes mistaken for drunkenness
  • May carry glucose tablets, an insulin pen, or wear a medical alert bracelet

What to do

  1. 1

    If they are conscious and can swallow: fast sugar now.

    Glucose tablets, a sugary (non-diet) drink, fruit juice or a handful of jelly sweets, roughly 15 to 20 grams of sugar.

  2. 2

    Reassess after 10 minutes.

    Not improving? Repeat the sugar. Improving? Follow with slower food, a sandwich, biscuits or a banana, so it does not crash again.

  3. 3

    If they become drowsy or unresponsive: nothing by mouth.

    Never pour a drink into someone who cannot swallow. Do your primary survey, put them in the recovery position and call 999.

High blood sugar

Hyperglycaemia builds more slowly: deep thirst, frequent urination, drowsiness, warm dry skin, and sometimes a sweet, fruity smell on the breath. It needs medical care: if they deteriorate or become drowsy, call 999. If you cannot tell whether sugar is high or low, treat as low and give sugar: it will not do serious harm in a hyper, and it can save a life in a hypo.

Do

  • Give fast-acting sugar early if they can swallow
  • Follow up with slower carbohydrate once they improve
  • When unsure whether high or low: treat as low

Don't

  • Do not give food or drink to anyone drowsy or unresponsive
  • Do not give diet drinks, they contain no sugar
  • Do not inject insulin for them

Common questions

What do you give someone having a hypo?

About 15 to 20 grams of fast sugar if they can swallow safely: glucose tablets, a sugary non-diet drink, fruit juice or jelly sweets. Reassess after 10 minutes, repeat if needed, then follow with something more substantial like a sandwich.

What if a diabetic person becomes unconscious?

Nothing by mouth. Open the airway, check breathing, place them in the recovery position if breathing normally, and call 999 immediately.

Related skills

Shock & FaintingPrimary Survey · DRABCSecondary Assessment

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First Aid Guru guides support learning and refreshing your knowledge. They are not a substitute for regulated, hands-on first aid training or for professional medical advice. In an emergency call 999 (UK) and follow the call handler's instructions.