Cat Poop Not Solid: Causes of Loose Stool in Cats
By Dr. Zubair Khalid, DVM, MS, PhD ·
If your cat's poop is not solid, the stool is somewhere on a spectrum from soft-serve to fully liquid. Occasional soft stool can follow a diet change or a stressful day, but loose stool that lasts more than a day or two, or comes with vomiting or lethargy, needs a veterinarian. This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- A single soft stool in an otherwise bright, eating, drinking cat is usually not an emergency. Watch the next 24 hours.
- Loose stool that lasts more than 48 hours, or that repeats, needs a veterinary visit even if your cat seems fine.
- Any diarrhea in a kitten is more serious because small bodies dehydrate fast. Call your vet the same day.
- Blood, black tarry stool, vomiting, hiding, or refusing food means call your veterinarian now.
- Do not give human anti-diarrheal medicines or antibiotics. Your veterinarian calculates any dose from your cat's weight and health.
What Loose Stool in Cats Actually Looks Like
Normal cat poop is firm, log shaped, and easy to pick up without leaving much residue. Color runs from light to dark brown. Slight day-to-day variation is normal.
Loose stool covers a wide range. Some owners describe cat poop half firm half soft, where the first part is formed and the tail end is mushy. Others see cat poop not fully solid, a pile that holds some shape but smears. At the far end is watery diarrhea with no form at all.
Vets often score stool on a visual scale. In one study of cats in multi-cat homes, fecal scores from 4 to 7 on a standard visual scoring system were defined as diarrhea [1]. You do not need the exact number. What matters is whether the stool holds shape, how often it happens, and whether your cat is acting normal.
The large intestine (colon) absorbs water and salts, stores feces, and houses healthy gut bacteria. When illness, parasites, or other problems damage the colon, diarrhea is often the result [2]. That is why colon problems tend to produce frequent small amounts of soft stool, sometimes with mucus, while small intestine problems tend to produce larger volumes.
If you also see jelly-like coating, read Why Is My Cat having loose stools with mucus? IBD vs Giardia vs Food Intolerance. If your cat is straining instead, see Cat Straining to Poop: Constipation or Something Worse?.
Common Causes of Cat Poop Not Solid
Causes range from simple and short-lived to chronic disease. The table below groups the most common ones.
| Cause | Typical clues | How urgent |
|---|---|---|
| Sudden diet change or new treat | Soft stool starts 1 to 3 days after the change, cat acts normal | Low, fix diet first |
| Food intolerance or allergy | Chronic soft stool, sometimes vomiting, itchy skin | Routine visit |
| Intestinal parasites (Giardia, coccidia, roundworms, hookworms) | Young cat, multi-cat home, mucus, weight loss | Same-day to routine |
| Bacterial imbalance or overgrowth | Soft to watery stool, gas, sometimes blood | Same-day if severe |
| Stress (new home, new pet, travel) | Loose stool within a day or two of the event | Low, watch closely |
| Inflammatory bowel disease (colitis) | Long-term soft stool, mucus, urgency, middle-aged cat | Routine visit |
| Low-grade intestinal lymphoma | Chronic diarrhea, weight loss, older cat | Routine to urgent |
| Toxins, foreign bodies, infections | Sudden severe diarrhea, vomiting, pain | Emergency |
Diet and Food Intolerance
Diet is the most common and most fixable cause. A sudden switch to a new food, too many treats, table scraps, or spoiled food can all loosen stool. Food intolerance can also cause long-term soft stool. In cats with chronic diarrhea, nutrition is a core part of long-term treatment, and vets often use specific food trials to identify triggers [2][3].
Parasites
Parasites are a major cause, especially in kittens and cats from multi-cat homes. In one study of young dogs and cats with diarrhea, 33.9 percent of the cats tested positive for coccidia, mostly Cystoisospora felis [4]. Other parasites found included Giardia, hookworms, roundworms, and tapeworms [4]. Watery or bloody diarrhea occurred in some cats infected with coccidia [4]. Kittens are hit hardest because they have less reserve.
Bacterial Problems and Gut Imbalance
The gut holds a complex mix of bacteria. When that mix shifts, diarrhea can follow. One study found that gut bacteria from diarrheic cats could impair the intestinal barrier and trigger colon inflammation when transferred into mice, with Gram-negative bacteria suspected as a main driver [5]. Another study of cats in multi-cat homes looked at several potential disease-causing bacteria and their link to diarrhea [1]. The takeaway for owners is simple. Gut bacteria matter, and testing helps your vet sort out which problem you are dealing with.
Chronic Inflammation and Lymphoma
Some cats have long-term colon inflammation, called colitis. Cats with chronic colitis tend to be middle-aged and are often purebred. In most cases the cause is unknown, though bacterial, parasitic, traumatic, kidney-related, and allergic causes are suspected [2]. The immune system's reaction inside the colon is often involved [2].
A more serious concern is low-grade intestinal T-cell lymphoma, which can look like chronic inflammation. In one study, the jejunum was the most consistently affected part of the gut in cats with either lymphoma or lymphoplasmacytic enteritis, followed by the ileum and duodenum [6]. This is why chronic diarrhea in an older cat deserves a real workup, not just a food change.
Stress and Sudden Changes
Cats are sensitive to routine changes. A new pet, a move, a boarding stay, or a loud household can loosen stool for a day or two. If your cat is eating, playing, and acting normal, stress-related soft stool often settles on its own.
Red Flags That Mean Emergency
Call your veterinarian right away or go to an emergency clinic if you see any of these.
- Blood in the stool, or black tarry stool
- Repeated vomiting along with diarrhea
- Your cat is hiding, weak, wobbly, or hard to wake
- Refusing food or water for more than 12 to 24 hours
- Diarrhea in a kitten under 6 months
- Diarrhea in a cat with kidney disease, diabetes, or another chronic illness
- A swollen, painful belly
- Straining with little or nothing coming out, which can signal a blockage
Dehydration is the main danger with severe or repeated diarrhea. Signs include tacky gums, skin that stays tented when gently pinched, sunken eyes, and lethargy. These are reasons to go now, not tomorrow.
Safe Things You Can Do at Home
These steps buy time while you arrange a vet visit. They do not replace one.
Keep Water Available
Offer fresh water in several spots. Some cats drink more from a fountain or a wide bowl. If your cat will not drink, that is a red flag.
Pause Treats and Table Food
Stop all treats, milk, and people food for a few days. Many cats are lactose intolerant, and milk makes diarrhea worse. Stick to your cat's regular food unless your vet says otherwise.
Do Not Fast Your Cat
Cats should not go without food for long. Fasting can cause serious liver problems in cats. If your cat is eating, keep feeding normal amounts.
Do Not Give Human Medicine
Never give loperamide, bismuth, or human antibiotics without veterinary direction. Some of these are toxic to cats, and the wrong antibiotic can make things worse. Your veterinarian will calculate any dose from your cat's weight and health.
Collect a Stool Sample
Scoop a fresh sample into a clean bag or container and refrigerate it. Bring it to your appointment. A fecal sample is one of the most useful tests your vet can run.
Reduce Stress
Give your cat a quiet room, a clean litter box, and space from other pets and kids. Stress reduction alone can settle mild cases.
Track the Details
Write down when the loose stool started, how many times a day, the color and consistency, whether there is mucus or blood, and what your cat ate in the last week. This history helps your vet narrow the cause fast [2].
What Your Veterinarian Will Check
Your vet will start with a full history and physical exam, including feeling your cat's belly and checking hydration [2]. From there, testing depends on how long the problem has lasted and how sick your cat is.
Common tests include:
- Fecal testing for parasites and bacteria, including flotation and concentration methods [4]
- Blood work to check organ function, electrolytes, and signs of inflammation
- Urine testing
- Abdominal x-rays or ultrasound
- Food trials to test for dietary causes of colitis [2]
- Endoscopy or biopsies if chronic disease or lymphoma is suspected [2][6]
For chronic diarrhea, your vet will try to classify it as small bowel or large bowel based on the pattern of signs, since the causes and treatments differ [3]. If the cause can be found and removed, that is the goal [2]. When no cause is found, treatment focuses on diet, gut health, and managing inflammation.
Prevention and Monitoring
You cannot prevent every cause, but you can lower the odds.
- Change food slowly over 7 to 10 days, mixing old and new.
- Keep treats to a minimum and avoid table scraps.
- Keep litter boxes clean and scooped daily.
- Use flea, tick, and parasite prevention as your vet recommends.
- Bring new cats to the vet for a check and fecal test before mixing them with resident cats.
- Weigh your cat monthly. Unexplained weight loss with soft stool is a reason to call.
- Watch for changes in stool shape, color, and frequency. Early notes help your vet.
If your cat stops pooping entirely, that is a different problem. See Cat Not Pooping but Eating Normally: Causes and When to Help and Cat Straining to Poop but Only Passing Mucus: Causes and Care.
Limitations and When to Contact a Veterinarian
This guide cannot tell you what is wrong with your specific cat. Only a veterinarian who examines your cat can do that. Use the timing below as a guide.
- Emergency now: blood or black stool, repeated vomiting, collapse, severe pain, suspected toxin or foreign object, or a kitten with watery diarrhea.
- Same day: diarrhea lasting more than 24 hours in a kitten, more than 48 hours in an adult, or any diarrhea with vomiting, lethargy, or refusing food.
- Routine visit: soft stool that comes and goes for more than a week, weight loss, or chronic mucus in the stool.
When in doubt, call your vet's office and describe what you are seeing. Front desk staff can help you decide whether to come in now or wait.
Frequently Asked Questions
Why is my cat's poop half firm and half soft?
This pattern usually means the colon is not absorbing water normally at the end of the digestive tract. Common causes include colitis, parasites, food intolerance, or a recent diet change. If it happens once or twice, watch it. If it repeats for more than a few days, book a vet visit.
Is soft stool in a kitten more dangerous than in an adult cat?
Yes. Kittens dehydrate much faster because they have less body water and smaller reserves. Parasites are also very common in young cats, and one study found coccidia in about a third of young cats with diarrhea [4]. Call your vet the same day if a kitten has loose stool.
Can stress cause loose stool in cats?
Yes. Cats are sensitive to changes in routine, and stress can speed up the gut and loosen stool. A move, a new pet, or a boarding stay often triggers a day or two of soft stool. If it lasts longer or your cat seems unwell, get it checked.
Should I fast my cat to firm up the stool?
No. Cats should not go without food for long periods because fasting can cause serious liver problems. Keep offering your cat's regular food in normal amounts. If your cat will not eat, that is a reason to call your vet.
How long can I wait before calling the vet?
For an adult cat that is acting normal, you can watch one or two soft stools over 24 hours. If loose stool lasts more than 48 hours, repeats, or comes with vomiting, lethargy, blood, or not eating, call your vet. For kittens, call the same day.
Related Articles
- Why Is My Cat having loose stools with mucus? IBD vs Giardia vs Food Intolerance
- Cat Not Pooping but Eating Normally: Causes and When to Help
- Cat Straining to Poop: Constipation or Something Worse?
- Cat Straining to Poop but Only Passing Mucus: Causes and Care
- Why Is My Cat Limping?
- Cat Straining to Poop but Nothing Comes Out: Emergency or Not?
- Cat Diarrhea On and Off: Causes of Intermittent Loose Stool
- Cat Loose Stools: What to Give and When to Worry
- Cat Poop Stuck in Anus: Why It Happens and What to Do
- Toxoplasmosis in Cats: Zoonotic Risk, Fecal Shedding, and Prevention
- Intestinal Parasites in Dogs and Cats: Zoonotic Potential and Public Health Considerations
References
- Presence of Potential Enteropathogenic Bacteria in Cats and Association With Diarrhea in Multicat Households. Journal of veterinary internal medicine, 2025.
- Disorders of the Stomach and Intestines in Cats - Cat Owners. Merck Veterinary Manual.
- Feline chronic diarrhea: causes and nutritional management. Veterinary and animal science, 2026.
- Occurrence of Cystoisospora spp. and other intestinal parasites in dogs and cats with diarrhea. Veterinary parasitology, 2025.
- Gram-Negative Bacterial Overgrowth Predominated by: Potential Association with Intestinal Barrier Impairment and Inflammatory Diarrhea in Cats. Veterinary sciences, 2026.
- Lesions Distribution, Nature and Severity Along the Gastrointestinal Tract in Cats With Low-Grade Intestinal T-Cell Lymphoma or Lymphoplasmacytic Enteritis. Journal of veterinary internal medicine, 2025.