Can Hookworms in Dogs Cause Vomiting Blood or Blood in Stool?

Hookworms are especially bad for puppies.
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It can be alarming to see your dog vomiting blood or to discover he has bloody diarrhea. It’s essential to find the cause quickly, since it’s likely to be something that can kill him, especially if he’s very small or young. Hookworms may be behind some of these problems.


Your dog can get hookworms if he eats an infected animal, such as a rodent or bird, or he can get them by contacting them in the soil or by swallowing hookworm eggs. Pups can also get them from their mothers when they nurse. While their normal residence is in your buddy’s intestines, hookworms also migrate through your dog’s intestines and end up in his lungs. Eventually he’ll cough those out of his lungs and swallow them, landing them back in his intestines.

Feeding Habits

Typically, hookworms connect themselves to your dog’s intestinal lining, where they chew holes and feed on the blood. They inject an anticoagulant to keep the blood flowing, allowing them to hang there and feed over a period of time. Every now and then a hookworm will disengage from its spot and find another place in the intestines to latch onto, but the old spot keeps bleeding. If too many hookworms are present your dog may end up being seriously anemic. Small puppies can die quickly from a hookworm infestation.


Symptoms of a hookworm infection are not always consistent. Dogs may have diarrhea, and if they do it may appear relatively normal or it may be bloody. The diarrhea may also look tarry or black, an indication of bleeding in the intestinal tract. Another symptom that indicates blood loss is very pale gums, which suggests anemia due to blood loss. Weight loss, unexplained weakness and itching may also indicate the presence of hookworms. Since hookworms do most of their damage in the intestines, they are unlikely to cause your dog to vomit anything, including blood.


Hookworms are relatively easy to control if treated promptly. Some heartworm medications kill hookworms, so the monthly dose of heartworm preventive that you give your dog may also clean out these pests. Check with your vet for the best medication to give your pet, but pyrantel pamoate and mebendazole are two drugs proven to be effective. Since the medication only kills the hookworms actually in the intestines, it has to be given at least twice, 30 days apart. If you have a pup that’s anemic, he’ll likely need additional treatment, possibly even a blood transfusion.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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