I have been told that if you catch a dog drinking their urine it's a sign that they might have Cushing's disease. What is Cushing's disease and why would it cause dogs to drink their urine?
Cushing's Disease (or Syndrome, which is the symptoms) is also known as Hyperadrenocorticism which, according to Merck is a illness that is either a result of:
Symptoms, in either case, commonly include:
So, why might it be a sign of Cushing's Disease when a dog drinks it's own urine? That would be a consequence of the first symptom I mentioned: extreme thirst. A dog that is extremely thirsty and has insufficient water resources may resort to drinking its own urine to help rehydrate.
Treatments are available, though they're not something you would administer at home. The actual treatment really depends on the source of the syndrome, but may include surgical intervention or radiation therapy.