We gave our domestic short hair cat (a neutered male rescue cat) an off the shelf dewormer tablet from a petstore the active ingredients were "Pyrantel embonate 230mg, praziquantel 20mg." Both of those ingredients can cause diarrhea

36 hours later he now has diarrhea, not bloody, but serious enough for him to foul himself in his sleep. He may also have taken a rat last night.

We are wondering is this just the dewormer working or should we be concerned about another cause? Is 36 hours too long for this to be linked?


If the diarrhea is still going on when you read this, you need to get your cat to the vet right now. It takes a very short time before cats get dehydrated.

Some cats get diarrhea after getting dewormed, but it is not a very common side effect for cats; the next time you deworm your cat, you might try another brand.

When a cat gets diarrhea from deworming it will often get better in less than 6 hours. If it lasts longer you need to get your cat to the vet.

Do not feed dry food to your cat if it has diarrhea; it will make the cat more dehydrated. Feed only wet food and water until your cat gets back to normal.

  • We took him to Vets 4 Pets who said he was fine. His eyes were also partially covered by a fixed third eyelids in both eyes which they said was normal. He is still struggling and is going to a second vet today. He is still active and playing but is not himself. Nov 15 '19 at 9:25
  • @SimonGibbs thank you for the update,i hope your cat gets well soon.a cat beeing ill for several weeks is not normal,i hope the new vet can help him and please give a new update when you know more about the cause of the problem. Nov 15 '19 at 14:37
  • 1
    sore bum, apparently. Nov 18 '19 at 11:52

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