Fever, coughing, low energy, loss of appetite: what to look for and when to call the vet

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Fever, coughing, low energy, loss of appetite: what to look for and when to call the vet

Q: How do I know if my dog has a fever?

A warm, dry nose isn't a reliable sign : plenty of healthy dogs have one. Look at the whole picture instead: low, shivering, turning away from the bowl or seeking out cool spots. A normal temperature sits between 38 and 39 °C, but it's the vet who takes it and reads it, and you never force a dog that resists.

Q: How do I bring down a dog's fever?

Above all, no human medicine : paracetamol, ibuprofen and aspirin are toxic to dogs. Keep him calm, cool, with water available, and call the vet. A fever that lasts or comes with other signs is worth an appointment: it's the vet who decides on any treatment.

Q: Why has my dog stopped eating?

A dog might turn down a meal over an upset, the heat or a touch of tiredness, then bounce right back. But a lost appetite is also one of the first signs of a health problem. The real question isn't « why » but « how long, and with which other signs »: low energy, vomiting or belly pain change everything.

Q: How long can a dog go without eating?

A healthy adult that's drinking and staying lively goes a day or two without eating with no trouble. Beyond 48 hours , call the vet, even if he seems fine otherwise. For a puppy, a senior or a very small dog, the threshold drops to 12-24 hours, and a puppy should never fast (risk of hypoglycaemia).

Q: How long can a dog go without drinking?

This isn't a stretch to « get through »: fresh water should be available at all times . A dog shouldn't go more than 24 hours without drinking; beyond that, he dehydrates fast and needs to be seen. Never force water with a syringe against his resistance (risk of it going down the wrong way into the lungs).

Q: Why is my dog coughing?

A dry, honking cough after crossing paths with other dogs often points to kennel cough , usually mild (it typically lasts 10 to 20 days). But a night-time cough in a small, older dog, a cough that makes breathing harder or one that lasts more than two weeks is worth an examination. In the meantime: rest, moist air and no pressure on the throat.

10 min read

A dog who turns away from his bowl, coughs or stays flat in his bed cannot tell you what is wrong. This guide gives you three markers: a dog's true normal temperature, how long he can go without eating depending on his age, and the signs that take you from simply keeping an eye on things to picking up the phone to the vet.

A dog hides what he feels

A dog cannot say that he is in pain. His pain, especially when it drags on, often goes unnoticed, even when he seems to be “coping” (WSAVA Global Pain Council). That is why the smallest change in his habits matters more than any dramatic symptom: it is often the only signal he sends you.

Reading each sign

Fever

Normal temperature sits between 37.5 and 39.2 °C; above 39.5 °C that is a fever, and above 41 °C the risk of complications climbs fast (Merck Veterinary Manual).
A warm, dry nose tells you nothing reliable: plenty of perfectly healthy dogs have one too.
What does speak is the whole picture: your dog stays lying down instead of coming to you, he shivers, seeks out somewhere cool or turns away from his bowl. Temperature is taken rectally with a suitable thermometer: a genuinely technical move, not a casual one. If your dog resists, do not force him, leave it to the vet.

Coughing

A dry, harsh cough that often ends in a retch, after contact with other dogs: this is often kennel cough, usually mild, and a runny nose or sneezing generally comes with it. It eases mostly over the first 5 days and typically lasts 10 to 20 days (Merck Veterinary Manual).
That same harsh cough, in a small dog who gets excited or pulls on his lead, can come from a collapsing trachea: the tube carrying air to the lungs gives way, a common problem in small breeds. The sound alone cannot settle which of the two it is: context is what counts. A harness beats a collar, and it is the vet who confirms.
A cough at night or at rest in an older dog, especially a small one, is not “just age”: it can point to a heart problem, and that is worth checking (2019 veterinary consensus).
A cough that comes on suddenly and violently, with the dog choking or pawing at his mouth, can come from an object stuck in his throat: that is an emergency. For a mild cough at home: rest, humid air (the bathroom after a hot shower), no pressure on the throat, and keep him away from other dogs for as long as he is coughing.

Low energy

A dog who sleeps more, plays less and suddenly withdraws is not being difficult: his body is conserving its strength.
“He is not complaining” does not mean “he is not in pain”.
A dog who stays lying down, who no longer comes to see you and no longer reacts to what usually delights him: call, especially if another sign comes with it.

Loss of appetite

Skipping a meal while staying bright and drinking is nothing serious in a healthy adult.
Refusing food for more than 48 hours, even with no other sign, warrants a call to the vet.
With a puppy, a senior or a very small dog, do not wait: the threshold drops to 12 to 24 hours, and a puppy should never go without food (risk of low blood sugar).

Before you call: what you can note down

These few observations are worth their weight in gold to the vet on the phone. You spot and describe; he diagnoses.

0 / 5

Can it wait, or do I call now?

This can be watched calmly

A healthy adult who skips a meal but drinks, plays and stays in good spirits.
A one-off vomit or a passing soft stool, with no blood, in a dog who stays active and in good spirits.
A slight cough with no breathing difficulty, in a dog who is eating and moving normally.
For these mild cases, watch him for a few hours, leave fresh water available, and call the vet if a new sign appears.

Call the vet

Refusing food for more than 48 hours, or refusing to drink for more than 24 hours.
A fever that drags on, or several signs at once: he stays lying down, he has stopped eating, and he coughs.
A cough that is not improving, that goes beyond three weeks, or that makes breathing difficult.
A puppy, an older or very small dog: if in doubt, call without waiting.

The signs that call for quick action

The further down the list you go, the more urgent it is.

Keep a close eye

Turns away from a meal but stays bright and keeps drinking
A slight occasional cough, dog still playing
A bit under the weather for a single day

Call today

Refusing food for more than 48 h, or water for more than 24 h
A fever that drags on, a dog who no longer gets up
A cough lasting more than three weeks or getting worse
Several signs at once, or a puppy or a senior involved

Emergency, head to the emergency vet

Blue, grey or very pale gums
Difficult or very rapid breathing at rest
Choking, pawing frantically at his mouth or unable to catch his breath after swallowing an object
Collapse, staggering gait, a seizure that goes on
A swollen, tight belly with straining to vomit but nothing coming up

Blue, grey or very pale gums; breathing that races at rest; a dog who is choking and cannot catch his breath after swallowing something; collapse, a staggering gait, a seizure that goes on; or a swollen, tight belly with straining to vomit and nothing coming up. In these cases, do not wait: a trip that turns out to be “for nothing” always beats arriving too late.

Do this right now

Call the vet or the emergency clinic to tell them you are on your way: it saves minutes once you get there.
Keep the dog calm and cool, without forcing him into a position: let him choose the one where he breathes best.
Give him nothing to eat, nothing to drink and no medication.

Call your vetor an animal poison control centre: without delay.

The assistant never replaces a vet. When in doubt, call.

WSAVA Global Pain Council — Guidelines for the recognition, assessment and treatment of pain (2022)
Keene et al. — ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs, Journal of Veterinary Internal Medicine (2019)
Canine infectious respiratory disease complex (kennel cough), Merck Veterinary Manual
Human medicines toxic to dogs (paracetamol, ibuprofen, aspirin), ASPCA Animal Poison Control Center
Normal Physiological Values for Dogs, Merck Veterinary Manual

Going further

guideHeatstroke in dogsIn summer, heatstroke can come on fast: learn to spot the signs and act at the right moment.Read the guide guideMy dog is vomiting or has diarrhoea: what to do, when to call the vetVomiting and diarrhoea often come with the same signs: this guide helps you tell the mild from the urgent.Read the guide guideSpotting a life-threatening emergency in your dogThe companion guide for knowing, at a glance, when to switch from watching to outright emergency.Read the guide guideMy dog is shaking: understanding and reactingAnother signal that often worries owners, rightly or wrongly: learn to decode your dog's trembling.Read the guide guideDog vaccines and boosters: the key milestonesThe best way to stay ahead: with regular check-ups, your vet picks up plenty of problems before they become visible.Read the guide guideThe first aid kit for your dogPut a kit together: the right reflexes and the right equipment to hand, while you get the vet's advice if needed.Read the guide

Frequently asked questions

How do I know if my dog has a fever?

A warm, dry nose is not a reliable marker: plenty of perfectly healthy dogs have one. Look at the whole picture instead: a dog who stays lying down without moving, who shivers, turns away from his bowl or seeks out somewhere cool. Normal temperature sits between 37.5 and 39.2 °C; above 39.5 °C that is a fever. It is taken rectally with a suitable thermometer: a genuinely technical move, best left to the vet if your dog resists.

How do I bring a dog's fever down?

Definitely no human medicines: paracetamol, ibuprofen (Nurofen) and aspirin have a far too narrow safety margin in dogs, and a dose meant for a human adult can poison him. Keep him calm and cool, with water available, and call the vet: a fever that drags on or that comes with other signs deserves a consultation, and it is the vet who decides on any treatment.

Why has my dog stopped eating?

A dog can turn away from a meal because something has upset him, because of the heat or a touch of tiredness, then bounce right back. But loss of appetite is also one of the first signs of a health problem. The real question is not “why” but “since when, and with what other signs”: if he stays lying down, vomits or has a sore belly, this is no longer just fussiness, it is a sign that deserves a call to the vet.

How long can a dog go without eating?

A healthy adult who is drinking and staying bright can go a day or two without eating with no trouble. Beyond 48 hours, call the vet, even if he seems normal otherwise. With a puppy, a senior or a very small dog, the threshold drops to 12 to 24 hours, and a puppy should never go without food (risk of low blood sugar).

How long can a dog go without drinking?

This is not a stretch of time to “get through”: fresh water should be available at all times. A dog should not go more than 24 hours without drinking; beyond that, he dehydrates quickly and needs to be seen. Never force water in with a syringe against his resistance: it risks going down the wrong way, into the lungs.

Why is my dog coughing?

A dry, harsh cough that often ends in a retch, after he has been around other dogs, often points to kennel cough, usually mild (it generally lasts 10 to 20 days, with a clear improvement from the first 5 days). That same cough in a small dog who gets excited can come from a fragile trachea; a cough at night in an older dog can come from the heart. A cough that is not improving, that goes beyond three weeks, that makes breathing difficult, or that comes on suddenly with the dog choking, deserves an examination. In the meantime, for a mild cough: rest, humid air and no pressure on the throat.

Updated on July 11, 2026Sources

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