Canine Diabetes Wiki
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Polyuria: Glucose cannot leave the body by itself--it must take water with it. Losing too much water means the body tries replacing it and this causes thirst, or polydipsia. When too much water is lost through excess urination and the excess drinking cannot make up for it, dehydration can occur.

Excessive thirst (medical term polydipsia [pah-lee-DIP-see-uh]; abreviated as PD) is a symptom of diabetes. Diabetic animals often drink incessantly because they are dehydrated from the cell-dehydrating effects of hyperglycemia, plus the effects of their bodies casting off the excess glucose through excessive urination, taking hydration with it. Diabetes mellitus is not the only condition or disease for which excess drinking is a symptom. [1][2][3][4] The "other" diabetes, diabetes insipidus, gets its nickname, "the thirsty disease", from the excessive drinking of its sufferers. [5] Urinary tract infections [6] can cause polydipsia and polyuria.[7]

Polydipsia is a sign or symptom indicating, due to lack of sufficient insulin, the body is unable to properly metabolize carbohydrates. With the addition of proper treatment, the symptom resolves, as the system now has enough insulin to accomplish this process properly.

  • NEVER restrict water for a diabetic pet! [8][9]   When there is poor or no blood glucose control, this is the only way it can be lowered--by literally flushing as much as possible out of the system. Regulation with the proper dose(s) of insulin will mean your pet no longer needs to drink abnormally because there is no excess of glucose to cause this.

Caregivers should provide adequate clean drinking water for their diabetic pets at all times. An animal's water consumption will diminish as it becomes more regulated and, if a switch is made from a dry-food diet to a wet-food diet, the animal will obtain more of its hydration from the wet food, which is often 70% or more moisture.

Polydipsia results in polyuria, or excessive urination. Together, the three "polys"--polydipsia, polyuria and polyphagia, excessive hunger, are vicious circles of uncontrolled or poorly controlled diabetes.

Normal non-polydipsic water consumption is about:

  • For dogs: less than 90 mililiters per kilogram (2.2 lb) of body weight [10] per day. [11] Another way to compute this is to allow 20 to 40 mililiters per kilogram (2.2 lb) of body weight. Using a 20 pound dog as an example, this should be 3 to 4 cups of water a day. [12][7]


  1. Kidney Disease. Pet Foster & Smith.
  2. Uterine Infections. Pet Education-Drs. Foster & Smith.
  3. Cushing's Disease. Pet Education-Drs. Foster & Smith.
  4. Richards, Mike. Increased Drinking & Urinating. Richards, Mike-Vet Info4Dogs.
  5. Nelson, Richard (2002). Polyuria, Polydipsia & Diabetes Insipidus. WSAVA.
  6. Diabetes Mellitus.
  7. 7.0 7.1 Lunn, Katharine F., James Katherine M. (2007). Normal and Abnormal Water Balance: Polyuria and Polydipsia. Compendium.
  8. FAQ's About Diabetic Dogs-Dr. Greco. BD Diabetes.
  9. Rickards, Rick. Canine Diabetes-FAQ's.
  10. Pounds to Kilograms/Kilograms to Pounds online converter. Open Toronto.
  11. Lyman, Ronald (2001). Diabetic Management is Doctor/Client Responsibility. DVM News Magazine.
  12. Polydipsia & Polyuria in Dogs.

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