Can I feed my dog right after deworming?

When a dog is dewormed, it is common for owners to wonder if they can feed their dog immediately afterwards or if they need to wait a certain amount of time. The answer depends on the type of dewormer used and the specific instructions provided by your veterinarian. In general, it is usually recommended to wait a few hours before feeding after administering certain dewormers in order to give the medication time to work effectively.

Quick Answers

Here are some quick answers to common questions about feeding dogs after deworming:

  • With most oral dewormers, it is recommended to wait 4-6 hours before feeding your dog again.
  • After giving an injectable dewormer, you typically need to wait around 24 hours before feeding.
  • Feeding too soon can decrease the efficacy of some deworming medications.
  • Check the label or your vet’s instructions to determine the appropriate waiting time for the specific dewormer used.
  • Feeding a bland diet for a day or two after deworming may help avoid GI upset.

How Different Dewormers Work

To understand why feeding should be delayed after deworming, it helps to know how common deworming medications work:

  • Fenbendazole – This oral dewormer works by interfering with the worms’ energy production and ability to move and feed. It needs time to pass through the GI tract and be absorbed into the worm’s body.
  • Praziquantel – Praziquantel causes paralysis and damage to tapeworms’ covering, leading to digestion and elimination. It’s quickly absorbed, so waiting before feeding allows it to take full effect.
  • Pyrantel pamoate – Pyrantel works by paralyzing the worms’ muscles, causing them to detach from the intestinal wall so they can be passed in the feces. Time is needed for the medication to take effect.
  • Ivermectin – Ivermectin binds to worm nerve cells, paralyzing and killing them. Waiting before feeding allows it to be sufficiently absorbed and distributed through the body.
  • Milbemycin oxime – Similar to ivermectin, milbemycin oxime works by disrupting nerve transmission in worms. A delay before feeding gives it time to take effect.

As you can see, most dewormers don’t work instantaneously. They require time to move through the dog’s system and act on the parasites. Feeding too soon can move the medication through the GI tract faster than intended.

Oral Deworming Medications

Oral dewormers are the most common type of medication used to eliminate intestinal parasites. Here’s a closer look at some typical oral dewormers and how long to wait before feeding after giving them:


Fenbendazole is a common broad-spectrum dewormer that kills roundworms, hookworms, whipworms, and tapeworms. It’s available under brand names like Panacur and Safe-Guard.

After administering fenbendazole, it’s recommended to restrict food for about 4-6 hours. This gives time for the medication to pass through the stomach and be absorbed in the small intestine, where it can start working on the worms.


Praziquantel is very effective against tapeworms. It’s sold under names like Droncit and D-Worm.

You should not feed your dog for around 4-6 hours after giving praziquantel. This allows the tapeworms to be exposed to the medication before new food enters the GI tract.

Pyrantel Pamoate

Pyrantel pamoate kills roundworms and hookworms. Common brands include Nemex and Strongid.

With pyrantel pamoate, it’s recommended to fast your dog for at least 4-6 hours afterwards. This gives the medication time to paralyze and detach the worms from your dog’s intestinal wall.


Piperazine is used primarily to treat roundworms. It causes paralysis and death of the worms over time.

You should not feed your dog for around 4-6 hours after administering piperazine. Allowing it to work before new food enters the GI tract improves its efficacy.

Milbemycin Oxime

Milbemycin oxime kills roundworms, hookworms, whipworms, and heartworm larvae. It’s sold under brand names like Interceptor and Sentinel.

It’s recommended to fast your dog for approximately 4-6 hours after giving milbemycin oxime. This allows the medication time to be absorbed and start paralyzing and killing off the worms.


Ivermectin eliminates common intestinal parasites and prevents heartworm disease. It’s an ingredient in Heartgard and other dewormers.

You should not feed your dog for 6-12 hours after administering ivermectin, depending on your vet’s instructions. This gives the medication time to distribute through the body and exert its paralyzing effect on worms.

Injectable Dewormers

Some deworming medications are administered by subcutaneous or intramuscular injection rather than orally. Here are some typical injectable dewormers and recommended waiting times before feeding:

Ivermectin Injection

An injectable form of ivermectin is available under brand names like Ivomec. It’s a very effective treatment for eliminating worms.

After injection, you should fast your dog for about 24 hours before feeding again. This allows time for the ivermectin to be distributed through the tissues and have its full effect on the worms.

Milbemycin Oxime Injection

Milbemycin can also be given by injection to treat parasitic infections. It goes by brand names like Milbemax.

It’s recommended to restrict food for approximately 24 hours after injecting milbemycin oxime. This gives the medication time to move through the body before new food enters the GI tract.

Moxidectin Injection

Moxidectin injection is used to treat and prevent heartworm disease along with killing intestinal worms. Brand names include ProHeart and Advantage Multi.

You should fast your dog for around 24 hours after administering moxidectin. This allows the medication to fully distribute through the tissues with time to act before new food is consumed.

Why Delayed Feeding Maximizes Effectiveness

There are a few reasons why it’s important to restrict food for a period of time after deworming your dog:

  • Allows dewormer to pass through GI tract – Oral dewormers need time to move through the stomach and be absorbed in the small intestine. Feeding too soon can push medications through too fast.
  • Enables full effect before new food intake – Dewormers need time to act on worms’ nervous systems or metabolisms. Waiting before feeding allows them to take full effect.
  • Prevents dilution of medication – Eating sends new contents into the GI tract which can dilute dewormer concentration and reduce contact time with worms.
  • Allows systemic absorption – Medications like ivermectin need to be absorbed from the GI tract into the bloodstream to reach worms in tissues.
  • Provides time to detach and die off – Paralyzed worms need time to release their grip on the intestinal lining and be passed before new food pushes through.

Following the recommended waiting period before feeding after deworming gives the medication the maximum chance to work effectively and eliminate your dog’s worms.

What to Feed After Deworming

After the required waiting time, you can feed your dog their normal diet again. However, some tips for the first meal post-deworming are:

  • Feed a bland meal – Rice, boiled chicken, cottage cheese, or scrambled eggs are gentle options.
  • Smaller portions – Don’t overwhelm the GI tract; feed smaller amounts at first.
  • Monitor stool – Check for normal vs. loose stool, which could indicate GI upset.
  • Call your vet – If you see worms in the stool, contact your vet right away.
  • Follow-up deworming – Dead worms may still pass after treatment. Discuss follow-up doses with your vet.

Transition back to their normal diet gradually over a day or two. Keep an eye out for decreased appetite, vomiting, or diarrhea after deworming, which could indicate medication side effects or a heavy parasite load.

What If My Dog Vomits After Deworming?

It’s not unusual for some dogs to experience mild vomiting or gastrointestinal upset after being dewormed. The medication can irritate the stomach and the dead worms passing through the GI tract can also cause nausea.

If vomiting occurs within the first 2 hours after giving an oral dewormer, you may need to redose as it’s likely the medication didn’t have time to be properly absorbed. Your vet can advise you on whether redosing is indicated.

To help calm your dog’s stomach, withhold food for a few extra hours until vomiting subsides. When you do feed, give a bland diet in smaller portions. Make sure your dog stays hydrated by offering water in frequent small amounts.

If vomiting persists more than 24 hours after deworming or your dog seems lethargic, you should consult your vet right away as more severe adverse effects could be occurring.

How Long Does It Take Dewormers to Work?

Deworming medications typically start working very quickly but may take days or weeks to fully eliminate an existing worm burden:

  • Paralysis of worms often occurs within hours but can take 1-2 days.
  • Death of worms can begin within 1-2 days but complete die-off can take weeks.
  • Detached dead worms are passed in the feces over 2-4 weeks.
  • Some larvae or eggs may still hatch and require follow-up doses.

So while you may see some dead worms passed in the first few bowel movements, it takes time for all worms to die off and exit the body. Follow your vet’s recommendations for any repeat doses needed down the line.

How Soon After Deworming Can I See Results?

You may notice the first dead worms being passed within 24-48 hours after giving a dewormer. However, it can take 2-4 weeks to see the full results and have all parasites eliminated from your dog’s body:

  • Medication kicks in rapidly but doesn’t kill worms instantly.
  • Dead worms detach over 1-2 days as paralysis sets in.
  • Elimination in feces occurs sporadically over 2-4 weeks.
  • Repeat doses may be needed as larvae continue to hatch.
  • Several rounds of treatment may be required for heavy infestations.

Monitor your dog’s stool during and after treatment to check for signs of dead worms being passed. It’s normal to still see worms in the stool on and off for up to 4 weeks after deworming as they continue to die off and get eliminated.

If you suspect the medication did not work effectively, bring a fecal sample to your vet for testing. They can check for eggs and determine if additional doses of dewormer are required.


Deworming medications require some time to work effectively at paralyzing and killing intestinal parasites. While exact waiting times before feeding depend on the specific dewormer used, most vets recommend fasting dogs for 4-6 hours after oral medication and up to 24 hours after injectable forms.

This fasting period allows dewormers to pass through the GI tract, get absorbed systematically, take full effect on the worms, and begin to eliminated from the body before new food and contents enter the intestines. Following label instructions and your veterinarian’s guidance can help maximize the effectiveness of deworming treatment and provide your dog relief from intestinal parasites.

Frequently Asked Questions

Can I walk my dog after deworming?

Normal exercise and walks are fine after deworming. Just be sure to pick up and properly dispose of their stool, which may contain dead worms being passed. Avoid dog parks and confined spaces where reinfection could occur.

How long after dewormer can my dog have milk?

Milk and dairy products should be avoided for at least 24 hours after giving your dog a dewormer. The high fat content can cause GI upset on top of the medication effects.

Can I bathe my dog after deworming medicine?

Bathing your dog is not recommended within 48 hours of administering a dewormer. Exposure to shampoos and water can interfere with proper absorption of the medication through the skin and GI tract.

Is lethargy normal after deworming a dog?

It’s common for dogs to have less energy and exhibit mild lethargy after being dewormed. The medication itself along with the worms dying off can cause them to feel under the weather. Monitor for other concerning symptoms and call your vet if lethargy persists more than 24 hours.

How often should dogs be dewormed?

Puppies should be dewormed every 2 weeks until 12 weeks old, then monthly until 6 months old. Adult dogs typically need deworming 1-4 times per year depending on risk factors. Follow your vet’s recommendations for your specific dog.

Key Takeaways

  • Oral dewormers usually require fasting dogs for 4-6 hours before feeding again.
  • Injectable dewormers necessitate around a 24 hour fasting period after administration.
  • This fasting allows the medication time to fully work and start eliminating worms from the body.
  • Feed a bland diet in smaller portions when food is reintroduced.
  • It can take up to 4 weeks to see the full effects with dead worms continuing to pass in feces.
  • Always follow label directions and your vet’s guidance on appropriate waiting period before feeding after deworming your dog.

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