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My cat didn't finish dewormer. Will it still kill the worms?

Updated On September 23rd, 2025

Pet's info: Cat | Maine Coon | Male | neutered | 13 lbs

I am pretty sure that one of my cats has worms (weight loss, wiping bottom on floor, blood in stool), so I gave both cats one worming tablet each this morning. The pills were quite big so I thought it would be better to crush the pill and mix with wet cat food, I did this but they wont finish the food. I'm just wondering, will the worming tablet still work even if they didn't take it all? When will I notice it has worked? Is it safe to give them the tablet again if it hasn't worked?

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on January 9th, 2018

If your cats didn't eat all the food, they probably did not get a high enough dose of the deworming medication to work correctly. The medication may kill some of the worms, but not all of them. You may notice dead worms in their feces indicating it's working, but sometimes nothing is seen at all. That is normal, and it doesn't mean the deworming medication isn't working. I would wait a week before giving them another deworming tablet, and this time give it to them whole. You may have to stick it in the back of their throat to get them to take it, but it's best for them to have the whole pill. After that, I would give them another deworming tablet in two weeks. This will make sure that all the worms are killed, as there will be worms in eggs which have not yet hatched at the time of the initial deworming treatment. They should then be dewormed every three months. Good luck, I hope this helps!

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