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Why Does My Cat Throw Up After Drinking Water? 5 Possible Causes

Cat vomiting
Image Credit: Tunatura, Shutterstock
Last Updated on November 16, 2023 by Christian Adams

Cats vomit for various reasons. Sometimes, you’ll notice that they throw up their food right after eating or when they finally get that hairball out. Other times, the vomit is clear. You may notice that your cat is drinking large amounts of water and then throwing up. Why is this happening?

In this article, we look at the three most common reasons that your cat throws up after drinking water and what you can do about it. We also look at two less common reasons that this happens so you can be aware of all the possibilities.


Water vs Clear Liquid

In cat vomit, clear liquid and water are different things. Clear liquid is liquid inside the digestive tract that is being brought up and forced out. Water is usually thrown up right after the cat drinks it.

Clear liquid and water also have different consistencies. Clear liquid is thick and sticky, while water is thin and runny.

The 3 Reasons Why Cats Throw Up After Drinking Water

Here are the three most common reasons that cats throw up after drinking water. If you notice that this is happening often, consult your vet. Frequent vomiting, no matter what the substance, can be a sign of illness.

1. They Drank Too Much Too Fast — Most Common Reason

When cats eat or drink too quickly, their stomach fills up and stretches. This sends a signal to the brain that the stomach needs to be emptied. If the cat drinks too much too fast, they will regurgitate what they just consumed. That’s why your floor is now covered in water, and your cat goes back to eating and drinking normally like nothing happened.

This is the most common and most harmless reason for this behavior. However, if you notice it happening repeatedly, it could be a sign of something more serious.

What to Do

A cat throwing up water occasionally because they drank too fast is not a cause for concern. Many cats don’t drink as much water as they should, so limiting their access to water is not a good idea. You can try to give your cat ice cubes to lick slowly so they don’t consume so much water at one time, but don’t take the water bowl away.

Chronic vomiting after drinking can lead to dehydration and kidney disease. Cats need to stay hydrated, so if you notice that your cat isn’t keeping water down, take them to the vet for an exam. There could be a health issue that needs to be corrected.

2. They’re Trying to Vomit a Hairball

A buildup of hair can form in your cat’s stomach from grooming. As cats lick their coats, their rough tongues pull off loose hair, which they then swallow. When the hairball gets big enough in the stomach, cats have to remove it by vomiting. You’ll know that it’s a hairball because it will be a long, tube-like shape of a hair clump. The tube shape forms as the cat forces the hair through the esophagus.

After your cat drinks water, they may feel the urge to vomit a hairball. While trying to force the hairball up, some of that water can come up instead. Your cat can also vomit clear liquid before a hairball. This is the liquid in the digestive tract that comes up with the force of vomiting before the cat succeeds at removing the hairball.

a cat that feels sick and seems to vomit
Image Credit: chie hidaka, Shutterstock
What to Do

If your cat is experiencing frequent hairballs, there are dietary supplements that you can use to help them pass the hair in their stool instead. You can also slow the frequency of the hairballs with regular brushing. By removing the hair before your cat has a chance to swallow it, you can stop it from forming a ball in their stomach so quickly. It’s unlikely that you’ll be able to prevent hairballs completely, but you can at least keep them from happening so often.

3. They’re Hungry

When cats are feeling hungry, their stomach acids build up to prepare to digest a meal. These acids can irritate the stomach and cause nausea. When your cat vomits, all that will come up is clear liquid, mucus, and/or yellow or orange bile.

If your cat drinks water, this can cause the stomach acids to build up faster, irritating the stomach quickly and causing them to throw up the water along with the acids.

What to Do

Cats that throw up bile due to hunger should eat smaller, more frequent meals throughout the day. If this happens in the morning, feeding your cat a small meal before bed may help them feel fuller overnight.

Automatic feeders can dispense a certain amount of food at certain times. You can set this to give your cat small meals overnight. If you aren’t concerned about your cat gaining weight, leaving food out at all times for them will work because they can eat whenever they want to.

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The 2 Uncommon Reasons Why Cats Throw Up After Drinking Water

The following two reasons for why your cat is throwing up after drinking water are not as common as the first three, but they are still good to be aware of. If you can’t determine why your cat is doing this, it’s best to ask your vet if one of the following possibilities could be the reason.

1. They Have Parasites

If your cat is suffering from a roundworm infestation, this is usually diagnosed by the appearance of worms in your cat’s poop. If the infestation is bad enough, it will cause vomiting. Your cat will often vomit any food or water that they consume if the worms are taking over their bodies.

Roundworms look like cooked spaghetti noodles. If you see them, there’s no mistaking what they are.

Sick cat medicines
Image Credit: one photo, Shutterstock
What to Do

Roundworms are gross, but if you see one, either in your cat’s litter box or in their vomit, pick it up with a paper towel. Put the paper towel and the worm into a plastic bag, and bring it to the vet, along with your cat. They will need treatment to clear the roundworm infection. Your vet can see the worm and know what type of treatment is necessary.

Unfortunately, there is nothing else that can be done besides killing the worms with medication from the vet. Your cat may need multiple doses of the medicine to ensure that the infection is completely resolved.

2. They Have a Metabolic Disorder

Certain diseases can increase your cat’s thirst. This will make them drink more water, sometimes too quickly, and then throw it up. An increase in your cat’s thirst is always a cause for concern because it’s a sign of several serious illnesses. Diabetes, kidney disease, and hyperthyroidism are just a few health conditions that can lead to cats drinking more water than they used to.

What to Do

If you notice that your cat is drinking more water than they used to and frequently throwing it up, they need to be evaluated by a vet to see if they have other signs of serious disease. If caught early enough, some health conditions are easy to treat. Others can be managed with medication and diet. It will mean your cat likely needs a blood test to determine what’s going on. Depending on the cause and severity of the issue, your cat may need to be hospitalized for care and given fluids for dehydration.

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There are several reasons that your cat will throw up after drinking water. Some of them are nothing to be concerned about, but if it happens frequently or is combined with other signs, it’s best to have them checked by a vet to rule out any health problems.

See also:

Featured Image Credit: Tunatura, Shutterstock

About the Author

Christian Adams
Christian Adams
Christian is the Editor-in-Chief of Excited Cats and one of its original and primary contributors. A lifelong cat lover, now based in South East Asia, Christian and his wife are the proud parents of an 11-year-old son and four rescue cats: Trixie, Chloe, Sparky, and Chopper.

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