Intestinal Worms in Dogs and Cats

7 min read


Why should the veterinarian check a stool sample?


Early diagnosis for the presence and type of intestinal parasite is vital. To do this the stool (only about a teaspoonful is needed) is mixed with a special solution, which makes the microscopic eggs more visible. Many veterinarians include the stool check as part of the annual health examination. (Note: Tapeworm eggs do NOT show up well in routine fecal analyses! Tell your veterinarian if you spot these rice-like segments in the stool or caught in the fur under the tail.)


How to Deworm a Dog or Cat


A dewormer solution can be used to rid your pet of worms. The type of dewormer solution will depend on the type of worm present. Not all worms respond to the same treatment and no single wormer works against all kinds of parasites. 


Additionally, some non-prescription wormers are quite ineffective in removing worms from the dog or cat.  Your veterinarian will have the best kinds of wormers available for the particular type of parasite your pet has.




Remove feces from your yard or litter box at least once a week. It also important you watch where your dog goes in the neighborhood dog park; these are often infested with intestinal worm larvae.


Use the correct wormer under veterinary supervision, and have your dogor cat's feces checked frequently in persistent cases. Do not mix wormers and do not use any wormer if your pet is currently taking any other medication, including heartworm preventative, without consulting the veterinarian. 


In the case of persistent reinfestations, some veterinarians will prescribe worming treatments on a routine basis all year long. Generally, prescription wormers will be safer and more effective (although often more expensive) than over-the-counter worm medications.


Can I Get Worms from My Dog or Cat?


Yes, worms found in dogs and cats are potential health hazards for humans, too. If hookworm larvae penetrate the skin they can cause "cutaneous larval migrans", a potentially serious and scarring inflammation results.


For example, ascarid (roundworm) eggs, if ingested, can cause a disease called "visceral larval migrans" where tiny worm larvae migrate through the person's intestinal wall and into the body tissues. They then grow to larger size almost anywhere in the body. Ocular disease is a common sequel "visceral larval migrans". 


Children are at most serious risk especially if play behavior is in an environment where dog, cat, or raccoon feces may be present... such as in a sandbox. A single adult Toxicara canis female can shed up to 100,000 eggs a day which pass into the dog (or cat's) environment with the stool. 


Please take the worming advice of your veterinarian seriously and adhere to strict sanitation principles whenever pets and children are in close contact.


To learn more about parasites of man and animals look at the Centers for Disease Control website at