How to Tell If Something Is Wrong With Your Dog

Name: How to Tell If Something Is Wrong With Your Dog
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-03

If you are asking yourself "how do I know if something is wrong with my dog," start by comparing your dog to their normal self today. Dogs cannot tell you where it hurts, so changes in eating, drinking, energy, breathing, bathroom habits, and behavior are your best clues. Trust your gut. If something feels off, it usually is worth a phone call.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

A dog who stops eating for more than 24 hours, vomits repeatedly, or has bloody diarrhea needs a vet call the same day.
Breathing that is fast, labored, or noisy at rest, plus collapse, seizures, or a bloated hard belly, are emergencies. Go now.
Subtle signs matter most in puppies and seniors, including sleeping more, hiding, pacing, or skipping meals.
Track the basics for 24 hours: food and water intake, urine and stool output, energy level, and any new symptoms.
Never give human medications, especially pain relievers, without asking your veterinarian first.

What Counts as Normal for Your Dog

Normal is personal. A greyhound sleeps 18 hours a day. A terrier puppy bounces off the walls. You know your dog's baseline better than anyone, and that baseline is the yardstick you should use.

Healthy adult dogs usually eat with interest, drink steadily, urinate and defecate on a predictable schedule, and greet you with their usual energy. Gums should be pink, not pale, blue, or bright red. Breathing at rest should be calm and quiet, and you should not see the belly heaving or the sides pulling in hard.

Puppies are different. They sleep a lot, eat several small meals, and have loose stools more easily than adults. A puppy who is quiet, cool to the touch, or refusing food is more concerning than the same signs in a healthy adult, because puppies dehydrate and crash faster.

How Do I Know If Something Is Wrong With My Dog? Signs Owners Often Miss

Many early illness signs are behavioral, not dramatic. Owners frequently report changes in activity, appetite, and comfort long before a diagnosis is made, which is why owner observations are treated as real clinical data in veterinary care [1].

Subtle clues

Sleeping more, or sleeping in a new spot away from the family
Slowing down on walks, lagging behind, or refusing stairs
Stiffness when rising, or trouble jumping onto the couch or into the car
Licking a paw, flank, or rear end more than usual
Bad breath, drooling, or dropping food while eating
Shaking the head or scratching at the ears (see How To Tell If My Dog Has A Ear Infection)
Scooting, or licking the genital area (see How Do I Know If My Dog Has A Uti)
A dull coat, weight loss, or a pot-bellied look
A visible worm segment in the stool or around the rear (see How Do I Know If My Dog's Got Worms)

What's wrong with my puppy symptoms

Puppies hide illness poorly but show it differently than adults. Watch for:

Refusing food or only picking at meals
Vomiting or diarrhea more than once
A distended belly that feels tight
Weakness, wobbling, or not wanting to stand
Crying when picked up or touched
Pale or white gums
A temperature that feels cold instead of warm

Any of these in a puppy under six months deserves a same-day call. Small bodies lose fluids quickly.

Main Causes and How Urgent They Are

Cause	Typical clues	How urgent
Dietary upset or food allergy	Itchy skin, ear infections, paw licking, loose stool, vomiting after eating a specific protein	Routine visit. Food allergens like chicken, beef, dairy, wheat, and lamb are common triggers, and diagnosis requires an elimination diet trial [2]
Gastrointestinal obstruction or foreign material	Vomiting, not eating, painful belly, no stool. Sand ingestion is one example, and in one study 35% of dogs that ate sand had radiographs consistent with obstruction [3]	Same day to emergency. Obstructions can become surgical emergencies
Heart disease (mitral valve disease)	Coughing, exercise intolerance, fast breathing at rest, fainting. Small breeds are commonly affected	Same day if breathing is labored or the dog faints. Otherwise routine
Endocrine tumor (insulinoma)	Weakness, collapse, seizures, muscle twitching, especially after fasting or exercise	Emergency if collapsing or seizing. Same day for weakness episodes [4]
Cancer	Weight loss, lumps, appetite change, lethargy, vomiting, lameness that does not improve	Routine to same day depending on severity. Cancer is a leading cause of death in older dogs [1]
Parasites (worms, giardia)	Scooting, visible worms, diarrhea, pot belly, poor coat	Routine visit with a stool sample
Infection (urinary, ear, skin, dental)	Straining to urinate, head shaking, odor, redness, tartar, drooling	Same day for urinary straining. Routine for mild ear or skin issues
Toxin exposure	Drooling, vomiting, tremors, seizures, collapse after eating something unknown	Emergency now

Red Flags That Mean Emergency

Do not wait and see with these. Call your veterinarian or an emergency clinic and go.

Trouble breathing, blue gums, or a dog who cannot lie down comfortably
Collapse, fainting, or a seizure that lasts more than a minute or repeats
A hard, swollen, painful belly with unproductive retching (possible bloat)
Straining to urinate with nothing coming out, especially in male dogs
Bleeding that will not stop, or a deep wound
Suspected toxin ingestion, including chocolate, grapes, raisins, xylitol, rodenticide, or human medications
Heatstroke signs: heavy panting, thick drool, wobbling, bright red gums
Pale white gums, cold ears and paws, or a dog who will not respond to you
Repeated vomiting or diarrhea with blood, or more than three episodes in a few hours
A puppy who is limp, unresponsive, or has a low body temperature

For poison exposures in the United States, call the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661. Both may charge a consultation fee.

Safe Things You Can Do at Home While You Wait

You cannot diagnose your dog at home, but you can gather information that helps your vet and keeps your dog comfortable.

Track the basics

Write down the time of each symptom. Note how much your dog ate and drank, how many times they urinated and defecated, and what the stool looked like (formed, soft, watery, bloody, black). Take a photo of anything unusual, including vomit, stool, or a lump.

Offer water, not food, if vomiting

If your dog has vomited once and seems otherwise bright, you can offer small amounts of water. Do not force food. If vomiting repeats, stop offering anything and call your vet.

Keep your dog calm and warm

Confine your dog to a quiet, safe space. Do not let them run, jump, or play if they seem weak or painful. Keep them warm with a blanket if they are shivering.

Do not give human medications

Never give ibuprofen, acetaminophen, aspirin, or human pain relievers. Many are toxic to dogs. Do not give leftover pet medications from a previous illness either. Your veterinarian will calculate any dose based on your dog's weight and health.

Check the gums and breathing

Lift the lip and look at the gum color. Pink is normal. Pale, white, blue, or brick red is a problem. Count breaths for 15 seconds and multiply by four. A dog at rest who is breathing more than 30 to 40 times a minute, or who is using the belly muscles to breathe, needs to be seen.

Do not induce vomiting unless told to

Some toxins cause more damage coming back up. Only induce vomiting if a veterinarian or poison control tells you to.

What Your Veterinarian Will Check and Test

Your vet will start with a full physical exam, including temperature, heart and lung sounds, gum color, hydration, abdominal palpation, and a weight check. Weight change is one of the most useful clues you can provide.

Depending on the signs, your vet may recommend:

Blood work (complete blood count and chemistry panel) to check organs, blood sugar, and infection
Urinalysis and a urine culture for urinary signs
Fecal testing for parasites
Radiographs (X-rays) for vomiting, coughing, or suspected foreign material. Sand ingestion, for example, is confirmed on radiographs [3]
Ultrasound for abdominal pain, suspected masses, or heart evaluation
Echocardiography for heart murmurs. Small-breed dogs with mitral valve disease are often staged using echocardiographic measurements and the presence or absence of clinical signs [5]
Blood glucose and insulin testing if weakness, collapse, or seizures suggest an insulinoma. Epileptiform seizures, weakness, collapse, and muscle twitching are the most commonly reported signs in dogs with this tumor [4]
Allergy testing or an elimination diet trial for chronic itching and ear infections [2]

Your vet may also ask you to keep a symptom diary at home. Owner-reported monitoring of clinical signs and quality of life is increasingly used to guide treatment decisions, including during cancer care [1].

Prevention and Daily Monitoring

Most of the work of catching illness early happens at home, not in the clinic.

Weigh your dog monthly on a home scale, or use the clinic scale at every visit. Unexplained weight loss is a red flag.
Do a weekly nose-to-tail check. Run your hands over the whole body, look in the ears, lift the lips, check the paws, and look under the tail.
Keep a simple log of appetite, water intake, stool, and energy. A one-line note per day is enough.
Stay current on parasite prevention, vaccines, and dental care.
Feed a consistent diet and introduce new foods slowly.
Puppies need more frequent vet visits, so use those appointments to ask about anything you have noticed.
Senior dogs benefit from twice-yearly exams, since cancer and heart disease become more common with age.

If you notice a change, do not wait for the next scheduled visit. A phone call costs nothing and often saves time.

Limitations and When to Contact a Veterinarian

No article can tell you what is wrong with your dog. Every case needs a veterinarian who can examine your dog, ask questions, and run tests. Use the guidance below as a starting point, not a diagnosis.

Call your veterinarian the same day if your dog:

Has refused food for more than 24 hours
Has vomited more than twice or has diarrhea more than three times
Is straining to urinate, or urinating more or less than usual
Has new weakness, wobbling, or trouble walking
Has a new lump, bad breath, or a persistent cough
Is a puppy with any of the signs above

Go to an emergency clinic now if your dog:

Is struggling to breathe or has blue gums
Has collapsed, fainted, or is having a seizure
Has a hard, distended, painful belly
Cannot urinate at all
Has uncontrolled bleeding or a major wound
Ate a known toxin
Is unresponsive, limp, or has a body temperature that feels very cold or very hot

Schedule a routine visit for gradual changes like mild itching, occasional head shaking, slow weight gain or loss, or a new small lump. If you are unsure which category fits, call your vet's office and describe what you see. The reception team can help you decide.

Frequently Asked Questions

How long can I wait if my dog is not eating?

A healthy adult dog can usually skip one meal without alarm, but more than 24 hours without eating warrants a call. Puppies, seniors, and dogs with other symptoms should be seen sooner. Not eating plus vomiting, lethargy, or pain is a same-day concern.

Can a dog be sick and still act normal?

Yes, and this is common in the early stages of many diseases. Dogs are wired to mask weakness, so subtle changes like sleeping more or slowing on walks may be the only clue. That is why routine exams and home monitoring matter.

What are the most common signs of illness in older dogs?

Weight loss, reduced activity, coughing, increased drinking and urinating, new lumps, and stiffness are the most common. Cancer is a leading cause of death in older dogs, so any new lump or unexplained weight change deserves an exam [1]. Heart disease also becomes more common with age, especially in small breeds [5].

Should I give my dog food or water after vomiting?

Offer small amounts of water first, and skip food for a few hours if your dog is still nauseated. If vomiting stops and your dog seems well, you can offer a small bland meal. If vomiting continues or your dog seems painful or dull, call your vet instead.

When should I go to an emergency vet instead of my regular vet?

Go to an emergency clinic for breathing trouble, collapse, seizures, a bloated belly, inability to urinate, heavy bleeding, toxin ingestion, or heatstroke. For mild, single episodes of vomiting or diarrhea in an otherwise bright dog, your regular vet can usually see you during normal hours. When in doubt, call ahead and describe the symptoms.

References

Development and Testing of an Owner-Reported Outcome Measure of Clinical Signs and Quality of Life in Dogs Treated With Chemotherapy. Veterinary and comparative oncology, 2026.
Clinical Signs and Offending Food Allergens in Canine Cutaneous Adverse Food Reactions in Malaysia, Singapore and Indonesia: A Prospective Study. Veterinary dermatology, 2026.
Clinical Features, Medical Management, and Patient Outcomes Following Sand Ingestion in 55 Dogs (2018-2024). Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001), 2026.
Clinical signs, management, and survival of 278 dogs diagnosed with insulinoma under primary veterinary care in the United Kingdom. Journal of veterinary internal medicine, 2026.
Echocardiographic Findings in Small-Breed Dogs With Myxomatous Mitral Valve Disease and the Severity of Mitral Regurgitation, Heart Size and Clinical Signs Myxomatous Mitral Valve Disease in Dogs. Veterinary medicine and science, 2026.