If your cat hasn’t used the litter box for a day or two, seems uncomfortable, or keeps straining to poop, constipation might be the reason. It’s a common issue, especially in older or less active cats. One product that many vets recommend to ease this problem is MiraLAX. Though originally made for people, it has become a gentle and effective solution for feline constipation when used correctly.
In this guide, you’ll learn what MiraLAX is, how it works, the right dosage for cats, and what to watch out for before using it.
What Is MiraLAX?
MiraLAX is the brand name for polyethene glycol 3350, an osmotic laxative. It works by pulling water into the intestines, which helps soften the stool and makes it easier to pass. Since it has no taste, smell, or colour, you can mix it into your cat’s wet food or water without much trouble.
Unlike harsh laxatives that force bowel movements, MiraLAX gently supports the body’s natural process by keeping the intestines hydrated. This makes it a popular option for both occasional constipation and chronic cases under a vet’s supervision.
When Do Cats Need MiraLAX?
Constipation can happen for several reasons. Your vet might suggest MiraLAX if your cat is struggling due to:
- Dehydration: Cats that don’t drink enough water are more prone to hard, dry stools.
- Low-fibre diets: Dry food or diets lacking moisture can slow down digestion.
- Hairballs: Especially common in long-haired breeds.
- Obesity or lack of exercise: Less movement can affect intestinal motility.
- Medication side effects: Some drugs can cause constipation as a side effect.
- Megacolon: A chronic condition where the colon becomes enlarged and weak.
If your cat hasn’t had a bowel movement for more than 48 hours or keeps trying to go without success, it’s time to consult your vet. MiraLAX can often help relieve the blockage safely when prescribed.
Recommended MiraLAX Dosage for Cats
The typical vet-recommended dose is ⅛ to ¼ teaspoon of MiraLAX powder once or twice a day, depending on your cat’s size and the severity of constipation. Always start with the lowest dose and increase only if advised by your vet.
Here’s a general guideline:
- Small cats (under 10 lbs): ⅛ teaspoon once daily
- Medium cats (10–15 lbs): ¼ teaspoon once daily
- Large cats (over 15 lbs): ¼ teaspoon twice daily (only if approved by vet)
Since MiraLAX is tasteless, mix it into your cat’s wet food or a bit of broth or tuna water. Never give it dry or without moisture, as this could worsen dehydration.
How Long Does It Take to Work?
MiraLAX doesn’t act immediately. Most cats will start to have a bowel movement within 12 to 24 hours, though in some cases it can take up to 48 hours.
If you don’t see results after two days, or if your cat becomes lethargic, starts vomiting, or refuses to eat, stop using it and contact your vet right away. Prolonged constipation can be a sign of a more serious issue.
Possible Side Effects of MiraLAX in Cats
MiraLAX is considered safe when used properly, but there can be mild side effects, especially if your cat’s dose is too high. These include:
- Loose stools or diarrhoea
- Gas or bloating
- Dehydration (if your cat isn’t drinking enough water)
Serious side effects are rare but can occur if MiraLAX is used long-term without monitoring. Always keep an eye on your cat’s hydration and appetite while using it.
When You Shouldn’t Use MiraLAX
Even though it’s generally safe, there are situations where MiraLAX isn’t suitable for cats. Avoid giving it if your cat:
- Is vomiting frequent
- Has bloody stool or diarrhoea
- Has kidney disease or heart issues
- Hasn’t eaten or urinated for over 24 hours
- Shows signs of severe pain in the abdomen
In these cases, constipation may be a symptom of a more serious underlying condition, and using MiraLAX could make things worse. Always have your vet rule out other causes before starting treatment.
Alternatives to MiraLAX
If MiraLAX doesn’t work or your cat refuses to eat it, your vet might recommend other treatments. Some popular alternatives include:
1. Lactulose Syrup
A sweet liquid laxative often prescribed for cats. It softens stool and is easy to adjust in dose.
2. Prescription Stool Softeners
Certain veterinary laxatives are designed specifically for cats and might be a better option for chronic constipation.
3. Dietary Changes
Switching to a high-fibre diet or increasing wet food intake can help regulate bowel movements naturally. Special vet-approved diets like Hill’s w/d or Royal Canin Gastrointestinal Fibre Response are great choices.
4. Pumpkin Puree
Adding a teaspoon or two of plain pumpkin (not the pie filling) to your cat’s meal can naturally increase fibre and moisture.
5. Increased Hydration
Encourage your cat to drink more by using a water fountain or feeding more wet food. Hydration plays a key role in preventing constipation.
How to Prevent Constipation in Cats
While MiraLAX can help relieve constipation, it’s better to prevent the problem in the first place. Here are some easy habits to adopt:
- Provide fresh water daily and consider a cat fountain to encourage drinking.
- Feed a balanced diet with enough moisture (wet food is ideal).
- Brush your cat regularly to reduce hairball buildup.
- Keep your cat active, especially if they are indoor-only.
- Monitor litter box habits—changes in frequency or stool consistency can reveal early signs of constipation.
When to See a Vet
Contact your vet if:
- Your cat hasn’t pooped in more than 2 days.
- You notice blood, mucus, or black stools.
- Your cat is straining, crying, or avoiding the litter box.
- MiraLAX doesn’t work after 48 hours.
Your vet may perform an X-ray, blood test, or abdominal exam to identify the cause and rule out conditions like intestinal blockages, tumours, or megacolon.
Conclusion
MiraLAX can be a safe, gentle, and effective treatment for cat constipation when used correctly and under veterinary supervision. It helps soften the stool, relieve discomfort, and restore regular bowel movements without harsh chemicals.
However, it’s not a cure-all solution. Chronic constipation, dehydration, or underlying medical issues always require a vet’s attention. Use MiraLAX only as directed, ensure your cat stays hydrated, and make diet or lifestyle changes to prevent future problems.
FAQs
Can I give MiraLAX to my cat without a vet’s advice?
It’s best not to. While it’s available over the counter, your vet needs to confirm that constipation is the actual issue and determine the right dose.
How long can I give MiraLAX to my cat?
MiraLAX can be used short-term for mild constipation or long-term for chronic issues, but only under veterinary supervision.
What can I mix MiraLAX with?
You can mix it into wet food, broth, or a bit of tuna water. Most cats won’t notice it since it’s tasteless.
Can MiraLAX cause diarrhoea in cats?
Yes, especially if the dose is too high. If this happens, stop giving it and call your vet.
Is MiraLAX safe for kittens?
Only if your vet recommends it. Kittens are more sensitive to dehydration, so professional guidance is essential.