Signs your dog is sick and when to call the vet

Your dog cannot tell you what hurts, and worse, evolution has trained them not to try. Showing weakness made a wild animal a target, so dogs developed a strong instinct to hide pain and illness, often eating, walking, and greeting you as usual long after something has gone wrong inside. The practical consequence is uncomfortable but worth saying plainly: by the time the signs are obvious, the underlying problem may already be advanced. That is the case for learning to read the subtle changes, the small drops in appetite or energy, the shift in how they breathe or how their gums look, rather than waiting for a crisis to announce itself.

One disclaimer first, because it matters most on a health page. This is general information to help you observe your dog and decide when to seek help. It is not a diagnosis and not a substitute for veterinary care. I am a writer, not a veterinarian, and nothing here can examine your animal. If a sign worries you, the right move is almost always to call your own veterinarian, who knows your dog's history, or to head to an emergency clinic if it cannot wait. When in doubt, AAHA's guidance is to err on the side of caution and contact your vet or the nearest emergency center (AAHA).

Step 1: Know your dog's normal

You cannot spot a change without a baseline, so learn what healthy looks like for your specific dog. A normal body temperature is 100.0 to 102.5°F, and a reading above 104°F or below 99°F is a reason for veterinary attention (VCA). Normal resting heart rate runs roughly 60 to 140 beats per minute in small dogs and 60 to 110 in large dogs, taken while the dog is calm. A normal breathing rate while resting calmly or sleeping is 15 to 30 breaths per minute, and a rate consistently above 30 at rest is abnormal. Healthy gums are pink and moist, and when you press them they should return to pink in under two seconds. Knowing these figures for your dog now, on a good day, is what lets you recognize trouble later.

Step 2: Watch behavior, appetite, and energy

The earliest signs of illness are usually changes in the ordinary, not dramatic symptoms. A dog who suddenly refuses meals, drinks much more or much less than usual, sleeps far more, hides, or loses interest in a walk they normally love is telling you something even when nothing looks broken (AAHA). Lethargy on its own can be minor: if your dog is otherwise bright, eating and drinking, and up for a short outing, it is usually reasonable to monitor for 24 to 48 hours (PetMD). But appetite is a sensitive gauge, and any dog that is not eating normally should be examined by a vet, especially if it comes with vomiting or weight loss (PetMD). Trust a deviation from your dog's own pattern more than any general rule.

Watch for the combinations, too. Lethargy plus vomiting, poor appetite plus diarrhea, or weakness plus a wobbly gait point toward a dog who needs to be seen rather than watched (AAHA, PetMD). Unintentional weight loss usually signals a more serious underlying problem and is worth a veterinary visit even if your dog seems otherwise content (PetMD).

Step 3: Read vomiting, diarrhea, and drinking

A single vomit in an otherwise normal, bright dog who keeps water down is usually not an emergency, and mild diarrhea that started in the last day in an active dog can often be watched briefly (PetMD). The picture changes fast when symptoms repeat. Contact your veterinarian if vomiting or diarrhea persists beyond about 6 to 12 hours, or sooner if you see blood in the vomit or stool (VCA). Repeated vomiting in a short window, for example several times in an hour, risks dehydration quickly and should be seen the same day. And vomiting or diarrhea paired with severe lethargy, collapse, an inability to keep water down, or signs of belly pain is an emergency, not a wait-and-see.

Drinking is its own signal. A clear, sustained jump in thirst, or a clear drop, is worth raising with your vet even without other symptoms, since both can accompany internal disease (PetMD). The same goes for urination: straining with little or no urine, or an inability to pass urine at all, is a medical emergency, because a urinary obstruction can let the bladder over-fill dangerously (PetMD). No stool for around 48 hours, with straining, also warrants a call (PetMD).

• Watch briefly: one vomit or mild new diarrhea in a bright, hydrated, otherwise normal dog (PetMD).
• Call the same day: vomiting or diarrhea past about 6 to 12 hours, repeated vomiting, or blood in either (VCA).
• Go now: vomiting or diarrhea with collapse, severe lethargy, belly pain, or no ability to keep water down (VCA).
• Always urgent: straining to urinate with little or nothing produced, or no urine at all (PetMD).

Step 4: Check breathing and gum color

Breathing and gum color are two of the most useful windows into how serious a situation is, and both are easy to check at home. Count your dog's breaths at rest by watching the chest rise and fall; a resting rate consistently above 30 breaths per minute is abnormal and a reason to contact your vet promptly (VCA). True difficulty breathing is a different category and is always a medical emergency: rapid or labored breathing, open-mouth or extended-neck breathing, or any honking, wheezing, or choking sound means go now, never watch it at home (VCA, PetMD).

Gum color is your fastest read on circulation and oxygen. Lift the lip and look: healthy gums are pink and moist (VCA). Pale or white gums can signal blood loss or shock, and blue, grey, or purple gums signal a lack of oxygen, both of which mean emergency care immediately. VCA lists pale or white mucous membranes, with a rapid heart rate and a weak pulse, among the signs of shock. If the gums are not their usual pink, do not wait to see whether your dog improves.

Step 5: Learn the bloat emergency cold

If you remember one true emergency in detail, make it bloat, known clinically as gastric dilatation and volvulus (GDV). VCA calls it one of the most serious non-traumatic conditions seen in dogs (VCA). The stomach fills with gas and can twist, sealing off both ends, and the condition progresses rapidly. The classic signs are restlessness and distress, a swollen or distended abdomen (often more obvious on the left side), excessive drooling, difficulty breathing, and the hallmark sign of repeated attempts to vomit that bring nothing up, the so-called unproductive retching, sometimes leading to collapse. A dog who is pacing, drooling, and retching without producing anything needs an emergency clinic immediately.

The reason to know this one cold is the clock. VCA states that immediate veterinary attention, within minutes to a few hours, is required to save the dog's life, and even uncomplicated cases carry a reported mortality of about 10 to 45 percent (VCA). Risk is highest in large, deep-chested breeds such as Great Danes, Saint Bernards, Weimaraners, standard poodles, and Doberman pinschers, and VCA notes that dogs over 100 pounds carry roughly a 20 percent lifetime risk. Any breed can develop it, though, so the signs matter for every owner. If you suspect bloat, skip home remedies and go straight to emergency care.

Step 6: Decide call the vet or go to the ER

The dividing line is not always obvious, so use this framing, summarized in the three tiers below. Mild, single, otherwise-normal signs are usually a monitor-then-call situation, with a daytime appointment if they do not resolve in a day or two (PetMD). Anything repeated, combined with other symptoms, or clearly painful moves up to a same-day call to your veterinarian. The true red flags belong to an emergency clinic right now.

Two practical notes. First, call ahead: AAHA's advice is to phone your veterinarian or the nearest emergency center when you are worried, which lets them prepare and tell you what to do on the way (AAHA). Second, for any suspected poisoning, alongside getting to a vet you can reach the ASPCA Animal Poison Control Center at (888) 426-4435, staffed 24 hours a day, every day, though a consultation fee may apply (ASPCA). Save that number now, before you need it.

The numbers worth memorizing

Do this, avoid that

Red flags: go now

Questions owners ask me most