Skip to main content

Cornell Richard P. Riney Canine Health Center

Longer. Healthier. Happier.

Diabetes in dogs


Diabetes mellitus is a condition that is shaped by the body’s inability to regulate sugar in the bloodstream. This disease is caused by a deficiency in the hormone insulin.  

Insulin is secreted by the pancreas, an organ in the digestive system, to control the amount of sugar (glucose) going into cells that need it for energy. Without enough insulin, sugar stays in the bloodstream, leading to higher blood sugar levels (hyperglycemia). The body’s cells then become starved for energy, and so they start making energy by breaking down stores of protein and fat.  

Over time, uncontrolled high blood sugar can lead to cataracts (cloudy eye lenses), or a life-threatening condition called diabetic ketoacidosis (DKA). This is a medical emergency that causes the dog's blood to become too acidic, and without prompt treatment, DKA can be fatal. 

Clinical signs 

The main clinical signs of diabetes mellitus include: 

  • Increased thirst  

  • Increased urination  

  • Increased appetite 

  • Weight loss 

If a dog develops DKA, the signs will be even more severe, including weakness, lethargy, poor or no appetite, vomiting, dehydration and more.  

Risk factors 

  • Middle-aged female dogs 

  • Breed predisposition (Samoyeds, miniature Schnauzers, poodles and more) 

  • History of pancreatitis  


Your veterinarian will evaluate clinical signs in combination with blood work and a urinalysis to diagnose diabetes. Additional tests may be needed to help rule out any coexisting conditions such as pancreatitis. 

Stress can cause temporary increases in blood sugar. If your dog has high blood sugar without any clinical signs of diabetes, your veterinarian may want to perform an additional test, such as a blood fructosamine level, which can differentiate a stress response from true diabetes.  


The goal of treatment is to reduce thirst, urination and appetite by keeping the blood sugar within a certain range.

Insulin is the cornerstone for diabetes treatment, and it is given by an injection under the skin twice a day at mealtimes — which should be the same amount of food given at consistent times. Diets that have higher fiber content may help in maintaining healthy blood sugar levels, but many dogs do well on any complete and balanced diet that they enjoy eating.  

Diabetes treatment may also involve managing other conditions that can decrease the effectiveness of insulin and make regulating blood sugar more difficult. This may include UTIs, conditions such as Cushing’s disease, hypothyroidism, obesity or pregnancy. 


After starting insulin, a monitoring test called a blood glucose curve is performed to check the sugar level range throughout the day. This test allows your veterinarian to determine if the insulin dose needs adjusting. Insulin may need adjusting more often in the early stages of treatment before finding an appropriate dose, and it should never be increased without your veterinarian's instructions. A blood glucose curve will be recommended any time the insulin amount is changed, especially if clinical signs recur, as part of your dog’s overall monitoring.  

Because it is possible for insulin to cause low blood sugar (hypoglycemia), your dog should always be monitored for signs of weakness, poor appetite, confusion, tremors or even seizures. If you think your dog might be experiencing these signs, Karo syrup should be applied to their gums. Then contact your veterinarian immediately for further directions.  


Dogs with diabetes generally require life-long insulin treatment. This can be successfully managed to give the dog a good quality of life. An owner’s commitment to managing their dog’s diabetes, as well as close partnership with their veterinarian, ultimately leads to the best outcomes.