Like all other animals (including humans), dogs contract worms and other parasites from time to time. Left unchecked, these parasites can lead to a variety of health problems and make your pup feel miserable.
Fortunately, there are a number of excellent products available that will help eradicate the worms living in your dog’s body and help him feel better again. We’ll recommend a few of the best below, but first, we’ll explain the basics of dog parasites and the treatment strategies that are generally employed to eliminate them.
Is that a serious question? How many things can you think of that are grosser than worms living in your pet’s body?
Aside from putting pineapple on pizza, I can’t think of anything that’s even close.
In all seriousness, worms and other parasites can cause a host of problems for your dog. Most low-level infestations produce only minor symptoms, but it doesn’t take long for a minor infestation to balloon into a life-threatening problem. So, it’s very important to do your best to keep your dog’s parasite load as low as possible.
Nevertheless, worms are pretty common for dogs.
All puppies get parasites, and most adult dogs will have a few wriggling around inside of them at various points in their lives.
Worms usually cause the biggest problems for puppies. Adults have stronger immune systems, which can mount a better defense against the invaders. However, stress, filthy conditions, and other health problems can occasionally leave adult dogs susceptible to parasites too.
Accordingly, puppies are generally treated for worms several times over their first six to 12 months of life, while adults are treated periodically (usually twice a year), or anytime an infestation is suspected or confirmed.
We’ll discuss some of the specific symptoms that are often associated with particular parasites later, but for now, let’s talk about the most common symptoms of a worm infestation. This includes:
There’s also one exceptionally extraordinary symptom that some owners note: You may observe a pile of worms on the ground after your dog poops or vomits. And before you ask, yes, the worms may still be alive.
‘Tis a ghastly sight indeed, but it needn’t cause you to freak out. This is a pretty common symptom, and you should be able to fix it pretty easily.
First thing’s first: Dogs can contract a variety of different parasites, and while many of them are, in fact, worms, others are not.
Many dog parasites are single-celled organisms called protozoans. Not only are protozoans different from worms, they aren’t even on the “animal” branch of the tree of life; they’re something entirely different. Some parasitic fungi also have common names containing the word “worm,” but they’re obviously not worms either.
However, the differences between a protozoan, a fungus, and a worm are not terribly important to the average pet owner. In practice, the term “worms” is used as a colloquial catchall for many of the various parasites that afflict dogs, and we’ll use it in this manner moving forward.
Pedantic nit-picking aside, the most common types of worms and parasites that affect dogs are explained below.
Roundworms are among the most common parasites that afflict dogs and puppies. Unlike many other worms, roundworms are pretty big (about 5 to 6 inches long), and they’re easy to see in your dog’s feces. They’re typically white, but they can also be slightly yellow in color.
However, just because your dog isn’t expelling roundworms doesn’t mean he isn’t infected, so routine testing and treatment are important.
While a handful of roundworms won’t cause your dog great distress, significant infestations can be quite troubling. Most commonly, roundworms cause diarrhea, abdominal pain, lethargy, and a pot-bellied appearance.
Some dogs may also lose their appetite, as the worms can fill the digestive tract, making a dog feel full. Occasionally, dogs may pass whole worms in their feces or expel them while coughing or vomiting.
Roundworms typically find their way into a dog’s body via the fecal-oral route (meaning that your dog will inadvertently ingest eggs, usually when sniffing another dog’s poop), but roundworms can also be passed to puppies via their mother’s breast milk. Typically, if one puppy in a litter suffers from roundworms, all of the puppies in the litter will contract them too.
Several different roundworm species can infect dogs, but dog roundworms (Toxocara canis) and canid roundworms (Toxascaris leonina) are the two most common. The former causes more serious problems than the latter and may also be transmitted to humans.
In fact, because roundworms can cause rather serious health complications for young children, the CDC recommends worming all puppies on a monthly basis and working closely with your vet to ensure all your pets remain roundworm free.
Roundworms have a direct lifecycle, but it is a bit more complicated than that of other worms. In some cases, the larvae will tunnel through various body tissues before maturing and making their way to the intestines. This can occasionally cause further complications, and (in rare cases) dogs may require surgery to remove roundworms or larvae.
Fortunately, with good hygiene and the right deworming medication, roundworms are relatively easy to eliminate. You can obtain roundworm-killing medications over-the-counter, or you can obtain them from your vet.
Hookworms are nasty little worms which can infect your dog’s small intestine. Once mature, these creepy little critters will pierce your dog’s intestinal tissues with their aptly named mouthparts and begin feeding on his blood.
In high numbers, these worms can end up consuming quite a bit of blood, which can lead to anemia. Without treatment, infestations can prove fatal – especially when they infect puppies.
Puppies often contract hookworms from their mother’s breast milk, but any dog can contract them from the environment. Most infestations probably occur when a dog inadvertently ingests hookworm eggs, which are shed in the feces of infected dogs (the aforementioned fecal-oral route). In some cases, hookworm larvae will gain access to a dog’s body by directly burrowing through the skin.
Diarrhea, weight loss, and reduced energy levels are the most common symptoms of hookworm infestations. Vets can confirm hookworm infestations through microscopic examination of your pet’s poop, but most will treat puppies and at-risk dogs for hookworms as a matter of course.
You can get medications that’ll eliminate hookworms over-the-counter or from your vet. Proper hygiene is an imperative component of treating hookworm infestations, so be sure that you dispose of your dog’s feces promptly and keep his crate and surroundings clean.
Note that while rare, humans can contract hookworms from the environment, and the results are occasionally pretty horrifying (graphic). These are definitely not a parasite to take lightly.
Whipworms (Trichuris vulpis) are another type of serious parasite that afflicts dogs. Although some dogs don’t seem to suffer serious symptoms from whipworm infestations, others can become quite sick.
Whipworms live in the large intestine and sometimes the cecum (the junction point for the large and small intestines) of dogs, where they cause a great deal of tissue damage. This can cause bloody diarrhea, lethargy, weight loss, and a general failure to thrive.
Whipworm infestations are contracted via the fecal-oral route, like most other nematodes. However, while dogs frequently suffer re-infestations from hookworms and roundworms, they are especially common where whipworms are concerned. Whipworm eggs are unusually resilient in the environment.
Accordingly, several treatments are usually recommended to treat whipworms, and strict hygiene measures are a must. Fortunately, humans can’t catch whipworms from dogs.
Whipworms are sometimes visible in your dog’s poop, but they are also quite easy to miss. In fact, vets often have trouble positively identifying them microscopically. When visible, they look like a thread that is thin at one end and wide at the other, and they’re about one-quarter of an inch long.
There are a few different medications that are effective against whipworms, including prescription and over-the-counter varieties.
Tapeworms are infamous for occasionally reaching gigantic sizes (up to 6 feet in some cases), but any living inside your dog’s body are unlikely to reach such mythological proportions. In fact, compared with some of the other worms discussed here, tapeworms are rather unimpressive foes that are pretty easy to treat.
Tapeworms are actually a much different kind of worm than the three previously discussed. Unlike hookworms, whipworms, and roundworms, which are all nematodes (roundworms), tapeworms are flatworms, called cestodes. But while few dog owners may care about the finer points of worm classification, most will care about another important difference between tapeworms and the roundworms discussed earlier:
Tapeworms have indirect, rather than direct, life cycles. This means that they require another species (which varies from one tapeworm species to the next) to complete their life cycles.
There are a few different tapeworm species that can afflict dogs, but the most common — the appropriately named dog tapeworm (Dipylidium caninum) — requires both fleas and dogs to develop fully. Dogs normally get them by eating infected fleas during their normal grooming process.
Other tapeworms that afflict dogs include the rabbit (Taenia pisiformis) and pork (Taenia solium) tapeworms. These can be contracted by eating contaminated food made from these proteins, or via the fecal-oral route, if your dog has contact with rabbit or pig feces.
Once inside your dog’s digestive tract, the tapeworms attach themselves to the small intestine. Unlike hookworms, which feed on the blood contained in the intestinal tissues, tapeworms simply help themselves to the partially digested food coming down the pipe.
Because tapeworms don’t feed on blood and infestations rarely occur in high numbers, they’re rarely responsible for causing serious illness. However, they’re still grody (technically speaking), and they may cause mild symptoms like an itchy butt and weight loss.
Tapeworm infestations can usually be identified by observing proglottids (shed tapeworm segments which contain eggs) in a dog’s feces. Proglottids are typically described as resembling small pieces of white or yellow rice. Dog tapeworms can infect people, but they’re treatable and rather easy to avoid with good hygiene practices.
You can purchase medications that will eliminate your dog’s tapeworm medication over-the-counter, although you can also get them from your vet if you prefer.
Protozoans probably do not affect dogs as commonly as true worms do, but because they can cause rather serious illness (and several species can be contagious to humans), they should be treated whenever present.
Coccidia, Cryptosporidium, and Giardia are among the most common protozoans to affect dogs. Most are transmitted via the fecal-oral route, but some can be spread through tick bites or bites from other dogs. Lethargy, weight loss, and diarrhea are some of the most common symptoms of protozoan infections, but muscle wasting, eye problems, and kidney dysfunction occur in some cases.
Some protozoan infections are very hard to diagnose, as the spores released in your dog’s feces can be very small and hard to see upon microscopic examination. In some cases, biopsies or blood smears must be analyzed to identify the protozoans causing the infection.
Unfortunately, you’ll need your vet’s help to treat most protozoan infections. In fact, a few protozoal diseases are so difficult to treat that euthanasia is sometimes recommended.
One over-the-counter medication (fenbendazole) is sometimes used to treat Giardia, but antibiotics and sulfa-drugs are usually the preferred treatment method for most others. Accordingly, you should always visit your vet anytime you suspect your dog is suffering from a protozoan infection.
Heartworms are much different than most of the other worms dogs get. Most worms (aside from ringworm) reside in a dog’s intestinal tract and spread via the fecal-oral route. By contrast, heartworms are spread via mosquitoes and they dwell in your dog’s circulatory system.
Young heartworms (called microfilariae) enter your dog’s bloodstream when he’s bitten by an infected mosquito. They then circulate around your dog’s bloodstream for a while as they develop into mature adults.
Once they become adults, they typically move to the heart, where they can cause serious damage to your dog’s heart muscle. This can cause dogs to become fatigued very quickly, as their cardiovascular system is unable to operate effectively. Eventually, many cases will cause fatal heart failure.
Unfortunately, treating heartworms is difficult business. You’ll likely need to have your dog undergo several diagnostic tests to reveal the extent of the infestation, and then he’ll need to receive three different injections of the only FDA-approved drug for treating heartworms in dogs — melarsomine.
Melarsomine is typically quite effective at killing any adult heartworms in your dog. However, it’ll take a while for your dog to flush these dead worms out of his body. The dead worm carcasses can make him very sick, and they may even cause a blockage of his pulmonary artery (the main artery connecting the heart and lungs), which will likely prove fatal.
Accordingly, melarsomine is usually given in a veterinary hospital so that emergency treatment can begin immediately if necessary. Additionally, you’ll need to prevent your dog from exercising for several months while his body rids the dead worms from his system.
If this all sounds dreadful, that’s because it is. It’s also quite expensive. In advanced cases, surgical removal of the worms may even be necessary. Guess how cheap that is.
Fortunately, heartworms are extraordinarily easy and affordable to prevent. There are several different medications, including ivermectin, selamectin, milbemycin oxime, and moxidectin, which kill heartworm larvae. They’re usually given periodically (once a month or so), and they prevent serious heartworm infestations from occurring.
However, none of these medications are available over the counter. This is primarily because many of these medications can be very dangerous for collies and several other herding breeds; moreover, they won’t kill adult heartworms and some vets worry about resistance problems developing if dogs aren’t also tested for heartworms regularly.
So, resist the urge to prowl the dark corners of the internet to find illegal versions of these products (which may not even be what they’re labeled as) and make a vet appointment if you suspect your dog is already infected with heartworms.
And even if your dog is symptom-free, be sure to ask about preventative medications on your next visit (most vets will recommend them anyway).
Ringworm is a very poorly named organism – it’s actually a fungus. And unlike the other worms and parasites we are discussing here, ringworm affects your dog’s skin, rather than his internal organs or gut.
We’ve written about ringworm before, so we won’t reinvent the wheel here. Ringworm typically causes characteristic ring-shaped rashes, which are surrounded by broken hairs. It’s rarely very serious for healthy adult dogs, but it is ridiculously contagious, and you can catch it from your dog. So, prompt treatment is always wise.
You’ll need your vet’s help to diagnose and treat the condition, as there aren’t any legitimate over-the-counter medications available to treat ringworm.
Unfortunately, there is no single worming medication that is effective against all of these different types of worms. You have to use the right drug to kill the specific worms in your dog’s body.
Some worm medications are available over-the-counter, but you’ll need a prescription from your vet to buy others. The three primary over-the-counter drugs used to treat worms in dogs include:
These medicines are usually prepared in one of three forms: Liquid, chewable tablet, or granular powder. Any of the three can simply be added to your pet’s food, but chewable tablets can also be given as a treat. Most chewable tablets are flavored to make them palatable, but the powders and liquids rarely are.
Some owners are concerned about giving medications to their dog to treat worms, so they’re eager to seek out “natural” remedies instead. Some of the most common recommendations include pumpkin or pomegranate seeds, garlic, and shredded carrots.
There’s probably nothing wrong with feeding your pooch pumpkin or pomegranate seeds, and carrots are used in plenty of dog foods. Garlic is a bit iffy, but it is probably safe in very small doses, and it is also used in a couple of dog foods.
Nevertheless, using these items in lieu of bona fide deworming medications is not a good idea.
First of all, most commonly used worming medications have been thoroughly tested and determined to be safe when administered in the proper dosage.
In fact, some of these drugs (or close analogs thereof) are used to treat humans. Fenbendazole, for example, has a ten-fold safety factor, meaning that you’d have to give your dog more than 10 times the prescribed dose before you’d see problems.
Secondly, there’s very little empirical evidence that suggests these treatments are effective. Some of these treatments appear to be somewhat effective at eliminating worms, but they’re unlikely to be as effective as the three medications mentioned above.
When you consider both of these factors and remember that worms can cause serious health problems for your dog (as well as your family), it becomes apparent that you don’t want to rely on unproven natural remedies where intestinal parasites are concerned.
Go ahead and feed your dog carrots or pumpkin seeds from time to time, but do so because your pup will find them delicious – not as a way of keeping your dog worm-free.
When you begin looking for a good wormer for your dog, you’ll need to make sure you select one that will treat the species infecting your dog, so review the following options carefully. Also, be sure to consider your dog’s specific needs.
For example, if your dog has a notoriously picky palate, you may want to opt for small tablets (which you can hide in a pill pocket or piece of cheese) instead of treat-style chews.
About: Safeguard 4 Canine Dewormer is a simple and easy-to-use worming medication that is effective against several different nematodes and one type of tapeworm. A powdered (granular) product, Safeguard 4 is packaged in small packets. When it is time to administer the medication to your dog, you simply mix it in with his food.
This medication is designed to be administered on three successive days, at a rate of 1 gram per 10 pounds of body weight. It is safe for adults, pregnant females, and puppies over 6 weeks of age.
About: Durvet Triple Dog Wormer is a high-quality dewormer that comes in chewable tablet form. Sold in packs of 12, you can add these tablets to your dog’s food or simply give them like a treat, as they have a taste most dogs like. These tablets are designed for medium to large dogs (you can find Durvet tablets for smaller dogs here).
You’ll need to administer one tablet for every 25 to 50 pounds of body weight. In other words, dogs weighing 25 to 50 pounds require one tablet, those weighing between 50 and 100 pounds require two tablets, those up to 150 pounds require three tablets, and giant dogs weighing more than 150 pounds require four tablets.
These tablets are safe for puppies 12 weeks of age or older and adult dogs. They are not, however, recommended for pregnant or lactating females, as the safety of these drugs for such use has not yet been verified.
About: Sentry HC WormX Plus Dog Dewormer is another option for owners seeking to kill most of the common roundworms, hookworms, and tapeworms that afflict dogs. These chewable tablets have a taste dogs love, and they can be given as a treat or simply added into your dog’s food.
Sentry HC WormX Dewormer Tablets are designed for dogs between 6 and 25 pounds. Administer one tablet for dogs weighing between 6 and 12 pounds, or two tablets to dogs weighing between 12 and 25 pounds. You can find Sentry Tablets for dogs weighing more than 25 pounds here.
These tablets are safe for puppies and adult dogs who weigh at least 6 pounds. However, the safety of these drugs has not yet been established for pregnant or lactating females.
About: Sentry WormX Double Strength Wormer is a liquid medication, which some owners find easier to use and administer than chewable tablets or granular products. The liquid can be administered directly by pouring it into your dog’s open mouth, or you can add it to your dog’s food.
This medication is designed to be administered at a rate of one teaspoon (5 milliliters) per 10 pounds of body weight. It is suitable for puppies and adult dogs weighing up to 120 pounds. It is not recommended for pregnant or lactating females.
The manufacturer recommends administering this medication on a monthly basis. A measuring cup is included with the medication to make it easy to administer the correct amount.
About: Bayer Tapeworm Dewormer for Dogs is a targeted worming medication specifically designed to eliminate tapeworms. Made in tablet form, you can administer this medication by simply giving it to your dog as a treat, or you can crumble it into your dog’s food.
This medication is designed for puppies who are at least 4 weeks of age, and it should be administered at the following dosages: Dogs less than five pounds need ½ a tablet, dogs between 6 and 10 pounds require 1 full tablet, and dogs between 11 and 15 pounds should be given 1 ½ tablets. Dogs in the 16- to 30-pound range need 2 tablets, while those weighing 31 to 45 pounds require 3 tablets. Dogs between 46 and 60 pounds require 4 tablets, while those over 60 pounds need 5 tablets.
You should always treat your dog anytime he has worms, but many vets and owners also administer dewormers to dogs on a regular schedule to help ensure their pet stays worm-free.
Typically, this means worming puppies at 2, 4, 6 and 8 months of age. This relatively rapid sequence of treatments is necessary for puppies for three different reasons:
Adults, on the other hand, are usually wormed once or twice a year, or anytime they are suspected of harboring an infestation. Additionally, vets will often worm dogs who haven’t been to the vet in a while, just to help eliminate any potential infestation.
As mentioned earlier, heartworm medications are different than those designed to eliminate intestinal worms. Your vet will explain the proper dosing schedule for your dog’s heartworm medicine, but most are designed to be administered once a month.
Although many owners and vets adopt a “shotgun” approach to worming their dog, it is always wise to identify the exact parasites living inside your dog, so you can utilize a targeted treatment.
This typically requires visiting the vet, so he or she can analyze your dog’s stool and determine which parasites (if any) are living inside your pet. However, this – like all other veterinary services – entails laying out a bit of money.
However, there is one other option: You can use a Perfect Pet Products Fecal Worm Test.
The product essentially consists of two small pouches; you’ll fill each with about a teaspoon’s worth of poop and then mail them to the lab. The lab will then look for the presence of roundworms, whipworms, hookworms, or coccidia (a common protozoan parasite), and provide you with the results within about 24 hours.
Not only is it a good idea to use one of these tests to determine which worms your dog has, it is also wise to use one a few weeks after worming your dog, to make sure that the treatment worked as intended.
If you select the proper deworming medication and administer it to your dog properly, the worms will usually die and be expelled along with your pup’s poop. And while you may not notice hookworms or whipworms in your dog’s feces, roundworms are often quite obvious.
However, the worms aren’t always dead when they come out.
While it can be shocking to see a living mass of writhing worms coming out of your dog’s rear end, this is normal (well, worms coming out of your dog’s butt is not what we’d call “normal,” but it’s no cause for concern). Such worms are in the process of dying, and they won’t last long exposed to the elements.
Worms are pretty common in dogs, and although there are a number of effective medications that’ll help treat them, you must be sure to select one that’ll be effective for the worms infecting your dog. Just be sure to review the information above carefully and always keep your vet in the loop when treating your dog for worms.
Have you tried any of the dewormers discussed above? We’d love to hear about your experiences. Let us know how they worked for you in the comments below.
Last update on 2018-12-15 / Affiliate links / Images from Amazon Product Advertising API
Ben is a proud dog owner and lifelong environmental educator who writes about animals, outdoor recreation, science, and environmental issues. He lives with his beautiful wife and spoiled-rotten Rottweiler JB in Atlanta, Georgia. Read more by Ben at FootstepsInTheForest.com.