Cat Foaming at the Mouth After Medication? (Here’s Why)

Cat Foaming at the Mouth After Medication

Is your cat foaming at the mouth after medication? Does your cat drool after medicine or spit out liquid medicine?

I’ve had to give my cats quite a few different medications over the years, both pills and liquid form. Here’s everything I’ve learned along the way, and what you should be aware of:

Why Is My Cat Foaming at the Mouth After Medication?

First of all, there is a difference between foaming at the mouth and drooling. Both of which commonly happen for various reasons.

When I talk about foaming from the mouth, I’m describing seeing excess saliva coming from your cat’s mouth which is frothy. Drooling is watery saliva, which looks very different.

The main reason for a cat to foam from the mouth after taking some form of medication is because it had a bitter taste. This isn’t uncommon, there are quite a few medications that cause this reaction.

I know Benadryl has caused one of my cats to foam. I also hear that atropine and Flagyl have a bitter taste and can cause foaming when the hit the back of a cat’s throat. It’s also possible your cat has licked some of their flea medicine off their neck.

As a general rule, if the medication you’re giving your cat has been prescribed and you followed the instructions, there shouldn’t be anything to worry about. It’s worth checking the instructions to see if it’s listed as a known side effect too.

It doesn’t hurt to contact your vet and check that it’s nothing to be concerned about. Always better to err on the side of caution.

Other Reasons to Explain Excessive Foaming or Drooling

Other Reasons to Explain Excessive Foaming or Drooling

Seeing your cat foaming or drooling after receiving medicine might actually be highlighting another issue your cat has. If your cat is also showing these symptoms when not taking medicine, it might be due to one of these reasons:

Oral Issues

I’ve had cats that have had a problem with their teeth before and this caused excessive drooling (not foaming). You might be able to see something is not right by taking a look under their gums.


Anxiety can cause a cat to drool or foam from their mouths. Have you moved home recently or put your cat through a potentially stressful change in circumstances? Maybe you’ve introduced another pet into the home? It’s worth exploring this to see if something is causing them to be anxious.


This sounds worse than it probably is in most cases. I had a cat that would lick a plant in a neighbors garden and froth at the mouth afterward, for example. I never did figure out which plant it was exactly, but it didn’t agree with him.

Spot-on Flea Treatments

The reason you apply spot-on flea treatments to the base of the neck is because this is supposed to be an area cats can’t lick. Well, some cats might be able to get to it. Especially if you’ve applied it a little off-center. It can’t be pleasant to taste, and it can cause foaming or froth from the mouth.


A dehydrated cat may foam or have bubbly saliva around their mouths. If it’s a particularly hot day, or you can see your cat hasn’t drunk anything, try and encourage them to drink some water. Not drinking for a period as short as 24 hours can start to cause some health issues.

How to Give a Cat Liquid Medication

How to Give a Cat Liquid Medication

If your cat has previously foamed after being given medicine, you might be wondering if you’re doing something wrong. Let’s be honest here, it’s not easy giving most cats medication orally.

Although they usually put up a bit of a fight, it’s actually not that difficult. Most oral medicines are absorbed transmucosal. This means they are absorbed once they are in their mouths, they don’t necessarily have to swallow the medicine quickly.

Here are some tips that should help next time you have to give your kitty some oral meds:

Use a syringe – Most medicines come with a syringe. Not only does this allow you to measure the exact amount you’re using, but it also makes it easy to put it into your cat’s mouth and plunge it.

Get help – It’s so much easier if there is someone else helping. One person can hold your cat so they’re comfortable and can’t move, while you focus on the syringe. It’s a good idea to wrap their bodies in a blanket so they can’t scratch or use their claws for traction if they panic.

Put in the corner of the mouth – If you try and shoot the fluid straight into their mouth, it’s likely to run out. The best place to plunge the fluid out of the syringe is into the corner of your cat’s mouth. Aim for the area next to their molars at the back of their mouth and squeeze the fluid so it 

Stimulate swallowing – After syringing the medicine into your cat’s mouth, remove the syringe and gently hold their mouth closed. Stroking under the chin or down their throat, as well as blowing their nose will stimulate a lot of cats to swallow what’s in their mouth.

Treats! – It’s a stressful time for you and your cat. Don’t forget to reward them with a tasty treat afterward to show your appreciation and relief.

In Summary

If your cat is foaming or drooling, don’t panic. It’s more often than not due to a reaction to the taste of the medicine you’ve given them. There are, however, some other possible causes, so it’s worth exploring these and giving your cat a health check.

I also included some tips that have helped me administer oral medications to my cats on a number of medications.

If you want to read more articles like, why is my cat foaming at the mouth after medication? Check out more health-related articles in the blog.

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