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My Dog is Lethargic but Eating and Drinking: 14 Reasons

Veterinary reviewed by Elizabeth Racine, DVM.

Many people have been there.

Your dog seems to be under the weather and not himself.

But when does it actually border on lethargy and what could your dog suffer from?

If your dog is lethargic but still eating and drinking, that’s a very non-specific symptom and could point towards a host of issues, all of which need to be taken care of.

For some cases of lethargic dogs, there are definitely home remedies while others require a vet visit

Let’s shed a bit of light on your dog’s lethargic behavior.

My Dog is Lethargic but Eating and Drinking

If your dog is lethargic but eating and drinking, common causes include overexercise, boredom, fear, poisoning, inflammation, or medication, as well as mental or chronic disorders.

The fact that your dog is lethargic but still eats and drinks is a good sign since that’ll avoid an emergency vet visit for nutrient deficiency.

However, some cases still need to be treated pretty quickly.

Others just depend on easily changeable external factors (such as exercise).

Also, the circumstances and other symptoms can be crucial.

Here are some signs that point towards certain causes (it’s not an exact science though and a vet visit might still be required to rule out other issues).

  • Have you recently changed the exercise regimen? Overexercise or boredom come to mind.
  • Recent rescue or traumatic event? Fear is common.
  • Right after a walk or after devouring bad food? Check for poisoning
  • Visible injury? Could indicate infection or inflammation
  • Recently put on meds?
Person drips water into their hand from a bottle and small dog drinks it.
Photo by alexei_tm on Shutterstock

Also, is your dog suffering from any of these symptoms as well?

  • Heavy breathing
  • Shivering
  • Shaking
  • Disorientation
  • Vomiting
  • Diarrhea
  • Changes in urination or defecation habits
  • Changes in drinking
  • Changes in behavior


Although the opposite is more common, it might just be that you ramped up your pooch’s exercise regimen too quickly.

If you’ve gone on an extremely long hike or just introduced a new activity such as biking or swimming, your dog might just be tired from that.

While this kind of acute overexercise is possible, it’s also possible that the exercise regimen has been too much for your dog to keep up with for weeks or months already.

If nothing has changed and you’re reasonably exercising your dog (which is essential), this is one of the unlikely causes of your dog’s lethargy.


If your dog is lethargic but still eating and drinking, it might very well be that your dog is bored out of his mind, perhaps eventually leading to depression or behavioral issues.

Some dog owners assume it’s just certain breeds that need mental and physical exercise but that’s plain wrong.

What’s true is that some breeds have higher exercise needs but all need to be kept busy to avoid boredom which can resemble lethargy.

Boredom can also lead to hyperactivity inside the house or overexcitement outside but both extremes are undesirable and should be looked into.

Fear or Trauma

Loud noises, negative experiences, unfamiliar surfaces, even a new environment can make some dogs fearful.

Especially if you’ve recently rescued a dog.

You’ll be the best judge of what might’ve led to that lethargy in your dog.

If your dog started to seem lethargic but is still eating and drinking recently, you should try to recall the day it started to figure it out.

Brindle-colored dog lying with the head on the floor stares into the camera, looking lethargic or sad.

It might only be a matter of time for your dog to stop drinking or eating altogether if the lethargy isn’t addressed.

Check this to see how you can build confidence in your dog and how to handle a rescue dog’s fear if you’ve recently brought one home.


Food poisoning is more common than you might think, considering there are a lot of foods your dog shouldn’t dig into due to toxicity.

Your dog could also just feel a bit down because he stuffed his face with that yummy dinner.

Seasoning alone suffices to upset a dog’s stomach to the point where they seem lethargic and sick but still drink, perhaps even more so to compensate.

If your dog picked something up while walking outside and doesn’t seem like himself anymore, keep poisoning in mind and consult a vet.

Infection or Inflammation

Inflammation can be caused by an infection which in turn could be the result of an injury.

You don’t see any visible injuries? Then your vet might order bloodwork to be done.

This is sometimes paired with a fever and can definitely be the cause of why your dog is acting lethargic.


Your dog was put on medication recently and now he’s lethargic but still eats and drinks?

That switch could be the cause.

Consult your vet to see if this behavior change is a known side effect and if the meds aren’t crucial at the moment.

You can try banning them from your dog’s daily to-do list and see if he improves and becomes more active again.

But remember to only discontinue the medication if your veterinarian gives you the okay to do so. Some medications shouldn’t be stopped abruptly.

Old Age, Disorientation, Depression

Dogs who just get older become calmer and calmer and if they’re lethargic but still drink and eat normally, everything might be okay with your dog’s health charts.

Disorientation, restlessness, or paranoia are serious symptoms and should be addressed.

If your senior dog is not only lethargic but stares at random points inside the house, is disoriented and circles a lot, you might look into canine dementia.

Diabetes, Heart Disease, Immune System Disorders, Cancer

The more serious causes of your dog’s lethargy include diabetes, heart disease, immune system disorders, and cancer.

While you may already know about your dog’s diabetes or immune disorders, there might be uncovered health issues and only the vet can help you determine if your dog might suffer from any of these conditions.

While there’s no reason to be on high alert just because your dog seems to not feel well for a day, you should definitely look into it if your dog behaves the same the next day without any apparent reason.

My Dog is Lethargic and Not Himself

If your dog is lethargic and not himself, you should look into common causes such as exercise issues, fear, poisoning, nutritional deficiency, or neurological disorders.

Neurological reasons are quite common causes for your dog not feeling like himself.

These causes affect senior dogs (hence why canine dementia plays a big role) but dogs of all breeds and ages can be affected too.

Behaviors that point towards neurological disorders include a lot of circling behavior or paranoid behavior where your dog also seems to see things inside the house.

Other signs of neurologic disorders can include abnormal gait, weakness, stumbling, trembling, seizures, changes in alertness, or other changes in behavior.

My Dog Seems Sad and Tired

Dogs who seem sad and tired can suffer from depression, neurological disorders, or just boredom or old age.

Everybody has bad days and good days but if your dog acts lethargic or overly sad, you should ask your vet.

In mild cases, it’s just boredom or your dog might have slight separation anxiety if one of his favorite people or dogs just left.

While dogs tend to get calmer with old age, it’s not common that they suddenly turn all sad and tired.

In general, you’re the best judge of your dog’s behavior and it’s important to put things into perspective.

Mellow dogs have a totally different starting point compared to an active, excited canine making a one-eighty turn to becoming sad, tired, or even lethargic.

If your dog suffers from a diagnosed condition already, this might be a particularly bad day for him.

When Should I Be Concerned About My Dog Being Lethargic?

You should be concerned about your dog being lethargic if he doesn’t react to stimuli and behaves weirdly for 24 hours or more while you should monitor the situation even more closely if he quits drinking and eating.

If you’re unsure, go the safe route and ask your vet.

Monitor your dog’s behavior closely, make sure they’re drinking and eating and get some exercise in and try to engage them.

Avoid disturbing them when they’re resting.

Once your lethargic dog stops eating or drinking, it might be more urgent to seek veterinary attention.

Disclaimer: This blog post does not substitute veterinary attention and does not intend to do so. I am not a veterinarian or pet nutritionist. If your dog shows any sign of illness, call your vet.

About Danielle

Equipped with 5+ years of expertise as a Rottweiler owner, I partner with licensed veterinarians and trainers to share research-backed and actionable advice for you and your furry friend.


Sunday 12th of March 2023

So the bad first, little blood in stool, dieareah for about a day now, acts weak, will stand but barely walks with no obvious pain? eats and drinks fine, no fever, is alert and wags tail a lot, he does kind of act like he’s in pain when I gently pull on front legs tho? But when he walks he doesn’t really Limp either, 4 yr old daschund.


Sunday 12th of March 2023

Hi James, from what you're describing, I'd definitely suggest you visit your vet, at least that's what I'd personally do. Blood, ongoing diarrhea, weakness, unsure if he's in pain - yep, that's a trip to the vet, dogs can be great at hiding their pain.

Lewis Tyner

Thursday 21st of July 2022

My dog was running and jumping last night, then after dinner I went outside with her and she was normal eating leaves off a bush out front. Within an hour she couldn't jump up on my bed. I picked her up and she laid next to me without moving. Finally this morning she started wagging her tail, stood up, and we walked around the house. Still not moving normal, but ate a dog biscuit and drink water. Throughout the day I've gone outside with her and she moves fine, just not fast. She was finding one kind of weed to eat and all day been hunting them when she gets up. It's almost been 24 hours, we just came back in from walking around the yard. She stopped wagging the tail and gingerly laid down at my feet. I thought she was getting better so didn't call the vet. Now the vets closed she's acting real puny again and I'm worried. It came on all of a sudden last night. Any ideas? Thank you.


Monday 25th of July 2022

Hi Lewis,

if your dog acts strangely after spending time alone outside and you're not exactly sure to what plants your dog had access to and if they're safe for dogs, it's best to consult your vet. If this persists, you should definitely schedule an appointment just to be sure.

Could be that she just ate too much and got an upset stomach or even diarrhea but it's best to have a vet rule out other issues.


Friday 1st of July 2022

My dog is fine when we go on walks, but the last few days I've noticed when we get home he becomes lethargic and sad, his walks havent changed


Saturday 2nd of July 2022

Hi Grant, it's hard to say what's making your dog seem lethargic without more info. Could it be that he's just exhausted from the walk? Or perhaps he's not exercised enough and craves more once he gets back - mental stimulation could help with that.

Also, it's best to rule out medical issues with a trip to the vet. Maybe he has pain when walking and really feels it after a long walk.