7 Things About Miralax for Cats

Today’s article is dedicated to unpacking all about Miralax for cats. Do you sometimes look at your cat and wonder whether it’s constipated? As with humans, cat constipation is very uncomfortable. Luckily, there are remedies for constipation out there.

One of them is Miralax. But, do you wonder how long it takes for Miralax to work? What are the side effects of Miralax or other questions? Take a read below! 

X-ray of cat with constipation, All About Miralax for Cats - I Love Veterinary

What Are the Causes of Constipation in Cats? 

Like humans, cats can become constipated. Constipation is a condition where the cat has trouble emptying their bowels. Often it is also associated with feces that is very hard.

Constipation can happen now and then in healthy cats, without it being a cause for worry. But, if it happens often, a more severe reason could be behind your cat’s troubles. 

Kidney diseases

Kidney diseases are frequently seen in senior cats. Issues with the kidneys will often cause the cat to become dehydrated. This will, in turn, cause the hardening of the feces, leading to constipation. 


Pain in the spine or joints can make it hard for the cat to defecate. Cats curl their back upwards when they go to the litter box. If cats are suffering from painful conditions, like osteoarthritis, this can make them reluctant to go.


Some types of drugs can cause a cat to be constipated. Either by directly affecting the bowels or by making the cat dehydrated. Examples of medicines that can cause issues are anesthetic and pain medications, iron supplements, antihistamines, and antacids. You should, however, never stop giving your cat prescribed medicine without first consulting a veterinarian. 

Fur ingestion 

When cats groom themselves, they ingest a lot of fur. Often they throw these hairballs back up. But, sometimes they move through the bowels, get stuck, and then cause constipation

Cat licking, All About Miralax for Cats - I Love Veterinary

What Are the Clinical Signs of Feline Constipation? 

A rule of thumb says your cat should poop, on average, once a day. But, don’t worry if your cat goes to his litterbox more or less than that. Cats are, as humans, unique. So are their physical needs.

How much your cat relieves itself depends on a lot of things like age, diet, or simply their personality. We all know how some cats refuse to go when the litter box is placed at slightly the wrong angle!

Monitoring how much your cat poops is rarely the best way to see if they are constipated. Some outdoor cats might poop outside, meaning you simply won’t be able to observe it all of the time. Some cats might only partially relieve themselves, leaving feces to continue accumulating in their bowel –  even though they appear to have regular bowel movements.

Some of the most common symptoms seen in constipated cats are: 

  • Frequent unsuccessful trips to the litter box 
  • Abnormal behavior in the litter box (crying, digging, uncleanliness) 
  • Loss of appetite 
  • Vomiting 
  • Lack of energy 

If you suspect your cat is constipated, it is vital to look into the underlying cause. Or at least, try to help relieve your cat’s symptoms. One of the ways you can help your cat is by administering Miralax. 

Cat in litter box, All About Miralax for Cats - I Love Veterinary

How to Use Miralax for Cats 

The best way to unconstipate a cat is to figure out the reason why it’s constipated and treat this. A veterinarian can help you with this and recommend a course of treatment. This is why we recommend you should always contact a veterinarian if your cat is ill. This way, you can together make a plan. 

The treatment that should solve the underlying problem (if there is any) and help shift the existing blockage in the intestines. This is where Miralax comes into the picture. Miralax is made for humans, but it works well for constipated cats as well. This is because it’s almost tasteless (cats are known to be picky at times) and easy to administer. 

Miralax comes as a water-soluble powder. This means that it can either be dissolved into the cat’s drinking water or maybe its favorite wet food! Mixing it into the food is generally recommended to ensure that your cat receives the right dosage. 

Miralax contains the active ingredient PEG 3350. The PEG molecules are hydrophilic (water-loving). This means they bind to water molecules in the intestines, stopping the water from leaving the intestines. This causes the stool to become larger and softer. It also stimulates the motility in the gut, making it move and move its contents again. 

Cat drinking water, All About Miralax for Cats - I Love Veterinary

What Is the Correct Miralax Dosage for Cats? 

A veterinarian will be able to guide you in indication as to how much Miralax you should give your cat. This can vary a lot from cat to cat as it depends on several things like: 

  • Your cats’ age and general health
  • The severity of the constipation 
  • Stool consistency 

As a general guide, cats need about ¼ of a teaspoon of Miralax twice daily. 

How fast Miralax works differs a lot from cat to cat. Some cats will experience relief within a few hours, others in a couple of days. Most owners report that they see a change within six to 12 hours of the first dose. Research suggests 8 hours when given to inpatients in hospitals. 

A few days with Miralax for some cats is enough to sort out the problem; other cats may need to have it administered for a few weeks. 

Cat and vet, All About Miralax for Cats - I Love Veterinary

Is Miralax Safe to use for Cats?

As long as Miralax is given under the instruction of a veterinarian, it is safe to give to your cat. 

There are, however, a few side effects one should be aware of:

  • Dehydration: Miralax binds the water in the gut, preventing it from entering back into the body. This can exacerbate dehydration. 
  • Diarrhea: Like with any laxative, it can go a little too far and cause diarrhea. 

Home Remedies for Feline Constipation 

Increase water consumption 

Dehydration is one of the main causes of constipation. Providing plenty of fresh water and changing it frequently can help combat this. You can encourage your cat to drink more by adding some flavor to the water. This can, for example, be tuna juice or beef broth. Always leave a “plain” water source for your cat as well. 

Add More Litter Boxes 

Cats are often particular about their litter boxes. They need to be a specific place, with the right level of cleanliness and much more. Often a cat will be unwilling to go to a dirty litter box – even if it’s only a tiny bit. Thus, having more litter boxes can encourage it to relieve itself. A good rule of thumb is two litter boxes per cat in the household. 

Probiotics or Fiber 

Probiotics are good bacteria that are often found in the gut. They promote healthy intestines and gut movements. They also help keep the stool soft—And helps to prevent constipation.  Fiber feeds the good bacteria in the gut, in many ways helping, just like the probiotics. 

Reduce Stress and Anxiety 

Our small furry friends get stressed easily. This can be due to an obvious reason like a new pet in the house, moving, or new loud noises nearby. Sometimes it’s even smaller things! But most cats will need some time to adjust, and in this period, they can become constipated from the stress. Calming pheromones (Feliway) or supplements (Zylkene) can, in this case, help your cat!

Cat litter box, All About Miralax for Cats - I Love Veterinary

When to Seek Help

In some cases, constipation can be treated at home without needing to visit the vet. But, if any of these symptoms arise, you should contact your veterinarian:

  • Vomiting
  • Abnormal eating pattern 
  • No bowel movement for two or more days 

These can be symptoms of more severe conditions when coupled with constipation. They will, therefore, need to be addressed by a professional. 


No one likes being constipated. It doesn’t matter whether you are a furry cat or a two-legged human. Luckily, Miralax can help your cat get its bowels moving again and get you both past the hard troubles.