Diabetes mellitus is a chronic endocrine disorder that occurs in dogs and cats. It is characterized by high blood sugar (hyperglycemia) and results when the pancreas is unable to produce enough insulin to meet the animal’s requirements.

Insulin is a hormone which is needed to transport glucose (blood sugar) as well as certain amino acids and minerals through the blood to energy-producing cells. When a lack of insulin occurs, glucose cannot move into the cells and the glucose level in the blood rises to abnormally high levels.


An animal with diabetes mellitus will exhibit some or all of the following symptoms: weakness, increased thirst, frequent urination, rapid weight loss, depression and abdominal pain. An animal may also show signs of either increased hunger or lack of appetite. In some animals, the sudden development of blindness due to cataract formation may indicate diabetes.


 Treatment requires a commitment of time and management from you, the owner. There is no cure for diabetes mellitus, but, as with humans, it can be controlled with insulin injections, diet and exercise management. With such therapy, your pet can lead a happy, comfortable life.

Once your pet has been diagnosed with diabetes mellitus, its specific insulin requirements need to be determined. As each pet’s insulin needs are unique and often vary from day to day, your pet may need to be hospitalized for 2-4 days in order to determine its specific needs. This is accomplished by your veterinarian giving the pet an insulin injection and testing the blood sugar levels at regular intervals throughout the day. These results are used to determine your pet’s initial insulin requirements. Your veterinarian may indicate these on a Glucose Curve Chart. Because your pet’s insulin needs may change once it returns home, due to changes in diet, exercise and certain environmental stresses, periodic re-evaluation over the next two weeks is recommended until satisfactory control is achieved. Once control is achieved, further evaluation should be completed every 2-4 months.


Diabetes mellitus in dogs and cats is caused by damage to the pancreas. Predisposing factors are: obesity, genetic predisposition, poor diet, hormonal abnormalities, stress and drugs. The sex of the animal can also be a predisposing factor. In dogs, females are affected twice as often as males and in cats, diabetes is more prevalent in males.