When is the Right Time to Put Your Dog to Sleep. Some of the common reasons to put your dog down include advanced age, terminal illness, intractable pain etc. There are some situations when putting a dog down is the only solution – and most of these reasons include when your dog is: Critically injured and won’t be able to survive In chronic pain that can’t be managed Just existing rather than enjoying a quality of life Very old and struggling. You’ll need to discuss the following difficult situations with your vet when: Chronic pain can be relieved with medication or treatment A terminal illness is diagnosed but symptoms aren’t apparent Drinking and appetite are reducing with incontinence increasing. Common Signs of Distress You know your dog better than anyone but often you can’t tell the level of pain – look out for: Vomiting and retching Loss of appetite and thirst Crying when touched or moved Hiding and excessive sleeping Rapid breathing Shaking and shivering even when it’s warm. More good days than bad. Bad days may include nausea and vomiting, unrelenting pain, and difficulty breathing – the quality of life suffers when there are many bad days one after another.