When your dog has worms and suddenly stops eating, it can feel like a double blow. Parasites are already harmful enough, but when they lead to appetite loss, it raises serious concerns.
We outline reasons why a dog with worms refuses to eat, what you can do at home, and when to seek veterinary help.
Dog Has Worms and Not Eating — Why It Happens
Worm infestations can interfere with your dog’s digestion, sap their energy, and make them feel nauseated or unwell, all of which contribute to appetite loss. In some cases, worms cause internal damage or inflammation that leads to vomiting, stomach discomfort, or even anemia. Tapeworms, roundworms, and hookworms are all common culprits.
A dog with a heavy worm burden may also become lethargic or weak, and the combination of parasites and not eating can escalate quickly.
Common Causes of My Dog Has Worms and Is Not Eating
Intestinal Worm Infestation
The most direct link between worms and loss of appetite is a high burden of intestinal parasites. Worms like roundworms, hookworms, and whipworms live in the gastrointestinal tract, where they steal nutrients and irritate the stomach lining.
This can lead to nausea, vomiting, diarrhea, bloating, and reluctance to eat. In puppies or small dogs, the effects can be especially dangerous.
Left untreated, a heavy worm load can cause intestinal blockage or severe nutrient deficiency, both of which suppress appetite.
Read more: Dog Diarrhea and Not Eating (Causes and when to worry)
Worm-Related Anemia
Some worms, particularly hookworms, attach to the intestinal lining and feed on blood. Over time, this can lead to anemia — a condition where your dog has fewer red blood cells than normal.
Anemia causes fatigue, pale gums, weakness, and lack of appetite. Dogs who are already fighting an internal parasite load may not have the strength or desire to eat, especially if their blood supply is compromised.
If you notice weakness, disinterest in food, and pale gums along with worm symptoms, anemia may be at play.
Worm-Induced Nausea or Vomiting
Worms can make your dog nauseated due to the toxins they release and the physical discomfort of an inflamed gut. Some dogs will vomit up worms, especially after meals, reinforcing the association between food and sickness.
Even if they don’t vomit, dogs with gastrointestinal upset often avoid food entirely or become picky.
The more advanced the worm burden, the more likely your dog is to feel nauseous and skip meals.
Complications from Deworming Medication
Ironically, treating worms can sometimes cause temporary appetite loss. Some dewormers irritate the stomach or cause mild digestive upset as the parasites die off and pass through the system.
Your dog might feel “off” for a day or two after treatment, particularly if the worm load was heavy. This reaction is usually short-lived but worth noting if appetite dips immediately after giving medication.
Secondary Infections or Underlying Illness
Sometimes a dog with worms who won’t eat may be dealing with more than just parasites. Worms can compromise the immune system or damage the intestinal lining, making the dog more vulnerable to bacterial infections.
In other cases, underlying conditions like liver disease or pancreatitis could be missed if worms are the obvious focus. If your dog has been treated for worms and still isn’t eating, there may be more going on internally.
What to Do If Your Dog Has Worms and Is Not Eating
First, make sure your dog has been properly diagnosed. A vet can confirm the type of worms present and prescribe the right dewormer.
If your dog has just been dewormed, give them a little time to recover. Offer bland, easy-to-digest foods like boiled chicken and rice in small amounts. Sometimes, appetite returns once the medication starts working.
Keep your dog hydrated. If they refuse food but will drink water, this is a good sign. You can add a bit of low-sodium broth to encourage drinking.
If your dog hasn’t eaten in over 24 hours or seems lethargic, weak, or has pale gums, don’t wait. These are signs the situation may be more serious.
Make sure to clean your dog’s environment thoroughly. Worm eggs can linger in feces or contaminated soil, leading to reinfection.
When to Call or Visit Your Vet
If your dog refuses to eat for more than 24 hours and has known or suspected worms, it’s time to call your vet.
Other red flags include:
Vomiting or diarrhea that persists for more than a day
Blood in vomit or stool
Pale or white gums
Visible worms in stool or vomit
Swollen belly or signs of pain when touched
Sudden weakness or collapse
In puppies, small breeds, or senior dogs, loss of appetite and worms can be dangerous very quickly. Seek immediate care if your dog is lethargic or rapidly declining.
Read more: Dog Upset Stomach Gurgling and Not Eating (What it means)
Key Takeaway
If your dog has worms and is not eating, don’t take it lightly. Parasites can drain your dog’s health and energy, especially when appetite is compromised.
Prompt deworming, supportive care, and close monitoring are key.
Always consult your vet if appetite doesn’t return quickly, or if other symptoms appear. With the right treatment, most dogs bounce back and regain their appetite once the worms are gone.