What are the signs of heatstroke in dogs?

A dog beginning to overheat pants faster and louder than normal, with a wide open mouth and a long tongue, and often seeks out shade or lies flat on cool tile unprompted. Gums and tongue can look brighter red than usual, and thick, ropey drool sometimes replaces normal saliva. Some dogs also become unusually clingy or restless in the minutes before more serious signs appear.

Without cooling, a dog can move from heavy panting to wobbling on its feet, vomiting, diarrhea, glazed eyes, or collapse within a fairly short window, sometimes under an hour from the first clear signs. Body temperature above roughly 41°C (106°F) puts organs under real strain, which is why speed matters more than trying to nurse the dog through it at home.

Move the dog to shade or an air conditioned space right away, offer small amounts of cool (not ice cold) water to drink, and use a fan or damp towels on the body while heading straight for veterinary care. Avoid ice baths or fully submerging the dog, since very rapid cooling can cause its own problems, and let a vet guide anything beyond basic shade, airflow, and water.

Call ahead to the vet practice while you are on the way if possible, so staff can prepare, and keep the cooling measures going in the car rather than stopping once the dog is loaded in. Do not wait to see whether the dog improves on its own before heading out, since heatstroke can worsen quickly even after panting appears to ease slightly.