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Low Blood Sugar (Hypoglycemia) in Dogs

By the Dog Health Handbook team · Updated · Fact-checked against current veterinary references (see sources)

Key takeaways

  • Signs: sleepiness, wobbliness, trembling, collapse and seizures.
  • Alert dog: give a small meal and take your dog to a vet.
  • Poorly responsive dog: rub corn syrup on the gums and go to a vet.
  • Common causes: too much insulin, puppies, xylitol and insulinoma.
  • Keep fingers out of the mouth and never pour liquid in.

Table of Contents

Research Signs First aid Causes Insulinoma Diagnosis Prevention FAQ Sources

Diabetes and Blood Sugar Quicklinks

Diabetes Causes Signs Treatment Diet Ketoacidosis (DKA) Low Blood Sugar Life Expectancy Diabetes Insipidus

Hypoglycemia (low blood sugar) in dogs means blood glucose below about 60 mg/dL.1 The most common causes are too much insulin in diabetic dogs, too little food in toy-breed and newborn puppies, xylitol poisoning, an insulin-producing tumor of the pancreas (insulinoma), and hard exercise in hunting and sport dogs. Severe infection (sepsis), liver disease and Addison's disease can also cause it.2,3,4 Signs include lethargy, sleepiness, unusual behavior, wobbliness, weakness, trembling, collapse and seizures.5,3 If your dog is alert with mild signs, give a small high-carbohydrate meal and then take your dog to a vet. If your dog is poorly responsive or trembling, the 2026 American Animal Hospital Association (AAHA) guidelines advise rubbing corn syrup on the gums with a cotton swab, keeping your fingers out of the mouth, and going to a vet immediately.5 Low blood sugar can be fatal, so every severe episode needs prompt veterinary care.6,7

Emergency: go to a vet now if your dog:

  • Has a seizure, collapses or is unresponsive5,3
  • Is diabetic and may have been given too much insulin3,8
  • Ate anything containing xylitol, even if it seems fine. Low blood sugar can start within 30 minutes, or be delayed up to 12 to 18 hours with some gums.9
  • Is a puppy that is weak, cold, very sleepy or won't nurse or eat3,4

Never pour liquid into the mouth of a dog that can't swallow, because it can be breathed into the lungs.10,5

What the Research and Guidelines Say

  • Safe first aid. AAHA's 2026 guidelines warn that "clients should not stick their fingers into a hypoglycemic patient's mouth."5
  • A common problem in newborns. A 2024 review calls low blood sugar "the most common metabolic alteration" in newborn puppies and a predictor of death.4
  • Xylitol and the liver. In a 2025 study of 95 dogs that ate xylitol, half developed raised liver enzymes, though none developed liver failure during follow-up that mostly ended at 48 hours.11
  • Insulinoma is rare. A 2025 UK study of over 2.2 million dogs found insulinoma in 0.003% of dogs a year, at a median age of 10.4 years.12

Signs of Low Blood Sugar

  • Lethargy, sleepiness or unusual behavior. The University of Missouri says "the first sign to look for is abnormal behavior."5,13
  • Weakness, wobbly walking or poor balance5,3
  • Trembling or twitching5,3
  • Vision problems, confusion or fast breathing3
  • Collapse, seizures or coma5,9

In diabetic dogs on twice-daily insulin, low blood sugar is most likely about 5 to 8 hours after an injection, when insulin peaks. Newer once-daily insulins have little or no peak.7,14

What to Do

  1. Alert, with mild signs: offer a small high-carbohydrate meal, then take your dog to a vet.5,13
  2. Poorly responsive or trembling: soak cotton swabs in corn syrup and rub them between the cheek and gums. Keep your fingers out of your dog's mouth, then take your dog to a vet right away.5 Cornell also lists honey on the gums.15
  3. Seizures or collapse: do the same and go to a vet immediately.5
  4. Diabetic dogs: don't give the next insulin dose until your vet advises.16,5

Sugar on the gums is only a temporary fix. Any puppy given syrup or honey "should then be taken to veterinarian immediately."3

Causes

  • Too much insulin in diabetic dogs: from a double dose, a dose given when the dog didn't eat, or improving insulin sensitivity, for example after an infection or pancreatitis settles2,1,5
  • Puppies: newborn and toy-breed puppies have small glycogen reserves and can become hypoglycemic after even short fasts.4,2
  • Xylitol: found in sugar-free gum, candy, mints, some peanut butters, baked goods and toothpaste. See xylitol poisoning.9,2
  • Insulinoma: a tumor that makes too much insulin, usually in older dogs17,12
  • Hunting dog hypoglycemia: in young, unconditioned or anxious working dogs6,3
  • Other diseases: sepsis, severe liver disease, liver shunts in puppies, Addison's disease and, rarely, other tumors2,18,3

Insulinoma

Insulinoma causes episodes of weakness, collapse, twitching or seizures that can be triggered by exercise, fasting or eating, and can look like epilepsy.17 It affects older dogs, and breeds at higher risk in the UK include Boxers, Flat-Coated Retrievers, German Pointers, Vizslas and West Highland White Terriers.12 In 40% to 50% of dogs the tumor has spread before diagnosis.17 Surgery is preferred. In one study of 48 dogs, median survival after surgery was about a year, and nearly 2 years for early-stage tumors.19 Dogs that can't have surgery can be managed with frequent small meals and medicines.17

Diagnosis

Vets confirm low blood sugar with a blood test. A low reading in a healthy dog with no signs may be a sampling error and should be repeated.2 Other tests look for the cause, including blood work, a urinalysis, liver function tests, an Addison's test and, for suspected insulinoma, insulin measured alongside glucose.2,17 Because trembling has many causes, checking glucose is an important early step.20

Prevention

  • Diabetic dogs: give the full insulin dose only after your dog eats at least half its meal, and never increase the dose without your vet.5
  • Keep corn syrup at home if your dog takes insulin.5,15
  • Puppies: feed small, frequent meals, and keep newborns warm and nursing.4,3
  • Keep xylitol products out of reach.9

Frequently Asked Questions

How does a dog act when blood sugar is low?

Sleepy, confused, wobbly or trembling. Severe cases collapse or have seizures.

How can I raise my dog's blood sugar at home?

If alert, give a small meal. If poorly responsive, rub corn syrup on the gums with a cotton swab and go to the vet.

Can I give my dog honey for low blood sugar?

Some vet sources list honey on the gums as an alternative to corn syrup. Get veterinary care right away.

Why is my diabetic dog shaking?

Trembling can be low blood sugar. Check glucose if you can and call your vet.

Can low blood sugar kill a dog?

Yes, if severe and untreated.

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Sources and further reading

This article was rewritten and fact-checked on October 23, 2026 against current veterinary references and specialist guidelines:

  1. AAHA Diabetes Management Guidelines for Dogs Task Force. Section 7: Troubleshooting in Diabetic Dogs. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  2. Barnes C, Williams K, Ruotsalo K, Tant MS. Testing for Low Blood Sugar. VCA Animal Hospitals, updated February 2024.
  3. Coile C. Hypoglycemia in Dogs: Signs, Symptoms, and Treatments. American Kennel Club, 2024.
  4. Fuchs KdM, Pereira KHNP, Xavier GM, Mendonca JC, Barreto RO, Silva RC, de Souza FF, Lourenco MLG. Neonatal hypoglycemia in dogs: pathophysiology, risk factors, diagnosis and treatment. Frontiers in Veterinary Science, 2024.
  5. AAHA Diabetes Management Guidelines for Dogs Task Force. Section 8: Client Education. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  6. Gillette R. Practice tips for the bird dog patient (Proceedings). dvm360, 2009.
  7. Williams K, Downing R, Ward E. Diabetes Mellitus: Insulin Treatment in Dogs. VCA Animal Hospitals, updated January 2024.
  8. Park JH, An JH, Kim SH, Choi HS, Kim TH, Oh YI, Seo KW, Youn HY. Case report: Fatal insulin overdose in a dog with type 1 diabetes mellitus: characteristics and successful management. Frontiers in Veterinary Science, 2023.
  9. Hayes C. Xylitol Toxicosis in Dogs. Merck Veterinary Manual, updated June 2025.
  10. Behrend E, Holford A, Lathan P, Rucinsky R, Schulman R. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. Journal of the American Animal Hospital Association, 2018.
  11. Lovell T, Peterson K, Kundu D, Mochel JP, Walton RAL. Incidence and risk factors associated with the development of a hepatopathy in dogs with xylitol ingestion (BSAVA Science Digest). Journal of Veterinary Emergency and Critical Care, 2025.
  12. Kraai K, O'Neill DG, Davison LJ, et al. Incidence and risk factors for insulinoma diagnosed in dogs under primary veterinary care in the UK. Scientific Reports, 2025.
  13. University of Missouri Veterinary Health Center. Diabetes. University of Missouri Small Animal Internal Medicine.
  14. AAHA Diabetes Management Guidelines for Dogs Task Force. Table 4.1: Insulin types. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  15. Cornell Richard P. Riney Canine Health Center. Managing Canine Diabetes. Cornell University College of Veterinary Medicine.
  16. AAHA Diabetes Management Guidelines for Dogs Task Force. Section 5: Monitoring Dogs Receiving Insulin. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  17. Buishand F. Functional Islet Cell Tumors in Small Animals. Merck Veterinary Manual, updated May 2024.
  18. Vaczy B. Hypoglycemia Due to a Jejunal Tumor in a Dog. EVC Voorjaarsdagen, Amsterdam (IVIS), 2014.
  19. Del Busto I, German AJ, Treggiari E, Romanelli G, O'Connell EM, Batchelor DJ, Silvestrini P, Murtagh K. Incidence of postoperative complications and outcome of 48 dogs undergoing surgical management of insulinoma. Journal of Veterinary Internal Medicine, 2020.
  20. Liatis T, et al. Causes of generalized tremors in 198 dogs. Journal of Veterinary Internal Medicine, 2025.

About this article

Last updated : written using the 2026 AAHA Diabetes Management Guidelines for Dogs, VCA, the Merck Veterinary Manual, the American Kennel Club and 2023 to 2025 research, plus International Veterinary Information Service (IVIS) proceedings and research published 2022 to 2026.

This page is for general information and is not a substitute for an exam by your veterinarian.