Warning Signs: How to Know If Your Dog Has Worms and What to Do

If you’ve ever Googled how to know if your dog has worms, you’re definitely not alone. As someone who works hands-on as a veterinary assistant (with a bit of a soft spot for pet nutrition), I’ve had this conversation with dozens of worried pet parents. And hey, I totally get it — your dog is family. So when they start acting weird, skipping meals, or leaving you “gifts” in the yard that look a little off… it’s natural to wonder if worms are the culprit.

Common Signs Your Dog Might Have Worms

1. Changes in Appetite or Weight

One of the earliest red flags I see in clinic? A dog that suddenly turns their nose up at dinner — or the opposite, scarfing down everything in sight like they haven’t eaten in days. Worms like roundworms and tapeworms compete for nutrients in the gut, which can mess with your pup’s appetite and lead to unexplained weight loss. If your normally chow-happy dog is looking thinner or uninterested in food, it’s worth paying attention.

2. Visible Worms in Stool or Vomit

Okay, brace yourself for this one. It’s not the prettiest topic, but it’s super important. Sometimes worms are actually visible — and yep, I mean in your dog’s poop or even vomit. Roundworms look a bit like spaghetti (I know, sorry), and tapeworms show up as little white rice-like segments around the anus or in fresh stool. I once had a client bring in a ziplock bag with a “sample” — and sure enough, those unmistakable rice grains confirmed it. Gross? Yes. Helpful? Absolutely.

3. Scooting or Excessive Butt Licking

You know that moment your dog starts dragging their behind across the living room rug? It might seem funny (and let’s be honest, we’ve all chuckled), but it can be a sign of irritation caused by worms or even impacted anal glands. If they’re scooting or going to town licking their behind more than usual, something’s up back there — and worms could be the reason.

Why Puppies Are Especially at Risk

If you’ve got a young pup at home, this part’s for you. Puppies are extra vulnerable to intestinal parasites — they can even be born with worms or pick them up through their mother’s milk. That’s why deworming is such a routine part of puppy care. In the clinic, I’ve seen far too many underweight pups with potbellies and dull coats, all because of a heavy worm load. The good news? It’s preventable — and treatable — with the right care plan.

Types of Worms to Watch Out For

1. Roundworms

These guys are super common, especially in puppies. Like I mentioned earlier, they look like spaghetti and live in the intestines. They’re spread through contaminated soil, feces, or even from mom to pup.

2. Tapeworms

Tapeworms have a segmented body and are often picked up when dogs swallow fleas during grooming. I always remind pet parents — if you’re treating for tapeworms, don’t forget flea control too. Otherwise, it’s a cycle that’ll just keep repeating.

3. Hookworms and Whipworms

These ones are nastier because they latch onto the intestinal wall and feed on blood. Hookworms can cause serious anemia, especially in young or small dogs. Whipworms are trickier to detect but cause chronic weight loss, diarrhea, and discomfort.

4. Heartworms (Different but Worth Mentioning)

While not technically an intestinal worm, heartworms are spread by mosquitoes and live in the heart and lungs. They’re not caught the same way, but I always bring them up because prevention is so key. Once symptoms show up, the disease is already advanced.

What to Do If You Suspect Worms

If you’re thinking, “Okay Camellia, this sounds like my dog,” don’t panic. First step? Call your vet and ask for a fecal test — that’s what we use to detect most intestinal worms. If I had a dollar for every time a dog came in acting a little “off” and the test came back positive, well… let’s just say I’d be treating myself to a lot more oat milk lattes.

And remember — catching it early makes all the difference. Worms can be serious, but they’re also super treatable with the right medication. More on that in the next section.

How Vets Diagnose Worms in Dogs

So let’s say you’ve spotted a few red flags and you’re thinking, “Okay, I need to get this checked out.” That’s where we come in — your vet team. One of the most common things I help with as a vet assistant is collecting and preparing stool samples for testing. I know, glamorous right? But honestly, it’s one of the most important steps to figuring out what’s going on.

Your vet will typically request a fresh stool sample (yep, you’ll want to grab that morning poop — sealed tight in a clean bag or container). We use a process called a fecal flotation test to look for worm eggs under a microscope. It’s not always foolproof — some worms don’t shed eggs all the time — but it’s a great place to start.

And trust me, no judgment. I’ve had clients show up with poop in sandwich bags, Tupperware, even wrapped in napkins (please don’t do that one). The important part is just getting it in so we can get answers.

Treatment Options: What Happens If Your Dog Has Worms?

1. Deworming Medications

Once we know what kind of worm we’re dealing with, treatment is usually pretty straightforward. Most vets will prescribe an oral dewormer tailored to the parasite. Some are one-time doses, while others require a short course over several days. If the infection is heavy, we might need to repeat the treatment after a few weeks to make sure we’ve wiped out all the stages of the worm’s life cycle.

From my side of the table, I always make a point to talk pet parents through the meds. I’ll never forget the time a sweet golden retriever named Max was prescribed a dewormer and the owner thought it was a supplement — totally missed the follow-up dose. So yeah, communication matters. Ask questions. Write stuff down. Your vet team wants to help.

2. Flea Control and Preventives

If tapeworms are involved, we always recommend treating for fleas too. Since dogs can pick up tapeworms by swallowing infected fleas, you’ve got to kill the source or the problem will just keep coming back. I usually recommend a good monthly flea/tick preventative — not only for tapeworms, but to avoid a whole buffet of issues like skin infections and Lyme disease.

3. Heartworm Treatments (If Needed)

If a heartworm test comes back positive (which requires a blood test, not a fecal exam), the treatment process is a whole different ball game. It’s more involved and sometimes requires injections, strict rest, and long-term care. The best approach? Prevent it altogether. Monthly heartworm preventives are way easier — and way cheaper — than dealing with an active infection.

How to Prevent Worms in the First Place

Now here’s the part I always emphasize in the exam room — prevention, prevention, prevention. Most of the time, worms are preventable with a few simple habits. And yeah, they’re habits that might not seem super exciting, but they make a massive difference in your dog’s long-term health.

• Pick up poop promptly — Worm eggs and larvae can live in soil for weeks or even months. Cleaning up quickly keeps the yard (and your shoes) parasite-free.
• Use year-round parasite prevention — Monthly heartworm meds often protect against roundworms, hookworms, and more. Ask your vet what’s best for your dog’s age, weight, and lifestyle.
• Regular vet checkups — Annual or biannual exams often include fecal testing, even if your dog seems healthy. It’s the best way to catch worms early.
• Keep an eye on eating habits — Dogs love to snack on gross stuff outside — dead animals, feces, random mystery snacks. Redirect that behavior and avoid off-leash scavenging adventures.

Can Humans Get Worms from Dogs?

This is a question I get all the time — and the short answer is yes, some dog worms can be transmitted to humans. It’s called zoonosis. The risk is higher in kids (because let’s face it, toddlers will touch anything), but adults can get infected too, especially if hygiene lapses. Roundworms and hookworms are the most common culprits.

Don’t panic though — this doesn’t mean you should bubble-wrap your pup. Just be smart about hand washing, poop pickup, and keeping dogs on regular deworming schedules. I always say: love your dog like family, but treat their poop like a biohazard. It keeps everyone safer.

What If Your Dog Keeps Getting Worms?

Okay, so what if you’ve treated your dog and the worms just keep coming back? This is more common than you’d think. And usually, it’s one of a few culprits:

1. Reinfection from the environment — If your yard, dog park, or neighborhood is a worm hotspot, your pup could be picking them up over and over again.
2. Not following up on deworming schedule — Some treatments need to be repeated or maintained monthly. Missing doses can leave room for a new infestation.
3. Untreated pets in the household — If you have multiple dogs (or even cats), make sure everyone’s treated. Parasites can easily spread between pets.

When that happens, I usually recommend a full deworming plan — not just for the dog, but the home and yard too. Sometimes it takes a village to kick parasites out for good.

Supporting Your Dog’s Recovery After Worm Treatment

Alright, so you’ve gone through the diagnosis, treatment, and now your pup is worm-free. Great! But now what? Just because the parasites are gone doesn’t mean your dog bounces back overnight. A lot of pet parents I work with are surprised at how long it can take for their dog’s energy, coat, and digestion to return to normal. Think of it like your dog recovering from the flu — they need a little TLC.

I always suggest keeping meals simple and nourishing for a week or two post-treatment. Easily digestible foods (like rice and boiled chicken or a vet-approved bland diet) can help soothe an irritated tummy. And don’t be shocked if you still see some weird poop during this time — it takes a bit for the gut to settle down.

One thing I love recommending — and use for my own rescue mutt — is adding a probiotic for a week or two. Whether it’s a supplement from the vet or even a spoonful of plain Greek yogurt (if your dog tolerates dairy), it helps restore healthy gut flora that might’ve been wiped out by parasites or meds.

When to Recheck With Your Vet

Depending on the type of worm and severity of the infection, your vet might ask you to bring your dog back for a follow-up fecal test. This is more common in cases where:

• The infection was particularly heavy
• Your dog had recurring worm issues in the past
• You’re in a high-risk area for parasites

These rechecks help confirm the medication worked and that no new infections have cropped up. I’ve had more than a few clients skip this step and then end up back in a few months wondering why the worms returned. Trust me — it’s worth that second appointment, even if your pup seems better.

How to Know If Your Dog Has Worms — and When to Be Concerned

By now, you’ve probably picked up on some of the telltale signs. But just to pull it all together, here’s a quick checklist you can refer to if you’re ever in doubt:

1. Is your dog losing weight without a change in diet?
2. Are they scooting or excessively licking their rear?
3. Do they have diarrhea or visible worms in stool?
4. Have they been exposed to fleas, dog parks, or other high-risk environments?
5. Is your dog a puppy that hasn’t been dewormed recently?

If you’re nodding along to more than one of these, it’s time for a chat with your vet. Early detection can save your dog from discomfort (and you from bigger vet bills down the line). I always say — trust your gut. You know your dog better than anyone.

Maintaining Long-Term Parasite Prevention

Here’s the thing — treating worms is important, but preventing them in the first place? That’s where the real power is. And it doesn’t have to be complicated. Here are a few things I practice with my own pets and recommend to every client:

• Year-round parasite preventatives: Monthly chewables or topicals that protect against worms, fleas, and even heartworms. Set reminders on your phone if you’re forgetful (like me!).
• Regular poop patrol: Pick it up right away — not just for sanitation, but to prevent your dog or other animals from stepping into a contamination zone.
• Annual wellness checks: Even if your dog seems totally healthy, yearly fecal exams and bloodwork can catch issues early. Prevention is always cheaper than treatment.
• Watch what they eat outdoors: Train your dog to leave gross things alone. A little obedience training goes a long way in keeping parasites (and vet bills) away.

Worms might be gross, sure — but with the right info and a bit of routine care, they don’t have to be scary.

Final Thoughts: Staying One Step Ahead of Parasites

Dealing with worms isn’t exactly the most glamorous part of dog ownership, but it’s definitely one of the most important. Over the years, I’ve seen everything from mild cases with quick fixes to heartbreaking situations where neglect led to serious illness. The difference always came down to one thing: awareness.

If there’s one thing you take away from all this, let it be this — knowing how to know if your dog has worms is half the battle. The other half? Acting on it. Your dog relies on you to be their advocate, their protector, and yep — their poop inspector. It might not be cute, but it’s real love.

References

• American Veterinary Medical Association (AVMA)
• Centers for Disease Control and Prevention (CDC) – Parasites in Pets
• Companion Animal Parasite Council (CAPC)

Disclaimer

This article is intended for informational purposes only and should not replace professional veterinary advice, diagnosis, or treatment. Always consult with your veterinarian if you suspect your pet may have worms or any other health condition.