I just noticed that my dog's tongue is a dark red instead of the pinkish color that it normally is. Are there any health concerns I need to be worried about?
A deep red tongue can be a symptom of carbon monoxide poisoning. It can be a sign of overheating particularly if rapid panting goes along with it. If the tongue has a bluish tinge making it dark it can be a sign of a problem with breathing or the heart. If you have a headache or others in the house feel sick I'd be worried about carbon monoxide in your home. If the dog was just out running or doing something exerting and its warm where you are it could be overheating. An allergic reaction to an insect sting could do this too. If the dog seems otherwise OK and no humans in the home have any symptoms you can wait and see if the color changes back to normal. The dog might just be cooling down.
Experience: 30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics