Cats with a blockage typically show a combination of repeated vomiting, loss of appetite, lethargy, and either straining in the litter box or no output at all. The specific signs depend on whether the blockage is in the digestive tract or the urinary tract, but both types can become life-threatening quickly. Knowing what to look for can make the difference between catching it early and facing a critical emergency.
Two Types of Blockage, Two Sets of Signs
When people search for blockage symptoms in cats, they’re usually dealing with one of two problems: an intestinal (gastrointestinal) blockage, where something is stuck in the stomach or intestines, or a urinary blockage, where urine can’t pass out of the body. Both are serious, but they look different and progress on different timelines.
Intestinal blockages happen when a cat swallows something it can’t digest, like a toy, hair tie, string, or piece of fabric. The object gets lodged in the digestive tract and prevents food and fluid from moving through normally. Urinary blockages occur when the urethra (the tube that carries urine out of the body) becomes plugged by crystals, mucus, or inflammation. Male cats are far more vulnerable to urinary blockages because their urethra is longer and narrower.
Signs of an Intestinal Blockage
The hallmark of a gastrointestinal blockage is vomiting that doesn’t stop. A cat with a stomach bug may vomit once or twice and bounce back, but a cat with an obstruction will vomit repeatedly over hours or days, often bringing up bile or foam even when nothing is left in the stomach. This happens because nothing can move past the blockage, so the body keeps trying to push it back up.
Other signs to watch for:
- Refusal to eat. Your cat may sniff food and walk away, or stop eating entirely.
- Abdominal pain. Your cat may hunch over, resist being picked up, or cry when you touch its belly.
- No bowel movements. A complete blockage prevents stool from passing. With a partial blockage, your cat may still produce small amounts of diarrhea as liquid squeezes past the obstruction.
- Lethargy. A blocked cat will often stop playing, hide, or seem unusually still.
- Drooling or lip-licking. Both are signs of nausea.
Linear foreign bodies deserve special mention. String, thread, ribbon, tinsel, and dental floss are especially dangerous because one end can anchor under the tongue while the rest travels into the intestines. The intestines bunch up around the string like fabric on a drawstring, which can saw through the intestinal wall. If you see string hanging from your cat’s mouth or rear end, do not pull it. Pulling can cause the intestines to tear.
Signs of a Urinary Blockage
A urinary blockage looks very different from an intestinal one. The defining sign is straining in the litter box with little or no urine coming out. Your cat may visit the box over and over, crouch and push, and produce only a few drops or nothing at all. This is sometimes mistaken for constipation, since the posture looks similar.
Other symptoms include:
- Crying or vocalizing in the litter box, as if in pain
- Bloody or pink-tinged urine
- Urinating outside the litter box
- Excessive licking of the genital area
- Vomiting (as toxins build up in the bloodstream)
- Hiding and withdrawal
- Loss of appetite
A complete urinary blockage is one of the most time-sensitive emergencies in veterinary medicine. When urine can’t leave the body, potassium levels in the blood rise rapidly, which can stop the heart. According to the American College of Veterinary Surgeons, a complete urinary obstruction can kill a cat within 3 to 6 days, but dangerous changes to heart rhythm and kidney function begin much sooner. This is not a “wait and see” situation.
Blockage vs. Constipation vs. Stomach Bug
One of the hardest parts for cat owners is figuring out whether their cat has a blockage or something less serious. Here’s how to think about it.
A stomach bug or mild food reaction usually involves one or two episodes of vomiting, possibly some diarrhea, and a cat that still drinks water and perks up within 12 to 24 hours. An intestinal blockage involves vomiting that escalates, a cat that gets progressively worse, and a complete refusal of food. The trajectory matters: a sick cat trends toward recovery, while a blocked cat trends toward deterioration.
Constipation involves straining to produce stool, and your cat may pass small, hard, dry feces. A urinary blockage involves straining to urinate, and the output is either absent or just a few drops. Look at where in the litter box the straining is happening. A constipated cat is trying to defecate. A urinary-blocked cat is trying (and failing) to pee. If you’re not sure which you’re seeing, check for urine clumps in the litter. No urine clumps over 12 to 24 hours in a cat that is repeatedly visiting the box is a red flag.
Which Cats Are Most at Risk
For urinary blockages, male cats are overwhelmingly more affected. Their narrow urethra is much more easily plugged. Indoor, overweight, middle-aged male cats on dry-food-only diets face the highest risk. Diet plays a significant role: dry food produces more concentrated urine, which encourages crystal formation. Research shows that cats maintained on high-moisture diets (wet food) have significantly lower recurrence rates of urinary tract problems compared to those on dry food alone.
For intestinal blockages, younger cats and kittens are the most common patients because they’re more likely to chew and swallow non-food objects. Cats that play with string, ribbon, rubber bands, or small toys are at particular risk. Some cats are repeat offenders, swallowing foreign objects more than once over their lifetime.
What the Vet Will Do
A physical exam is the first step. Your vet will feel your cat’s abdomen for pain, a distended bladder, or a mass in the intestines. For suspected urinary blockages, a hard, enlarged bladder that the cat can’t empty is often detectable by touch alone.
For intestinal blockages, diagnosis usually requires imaging. X-rays can reveal some swallowed objects directly, especially dense materials like bones or metal. They also show patterns of gas and fluid buildup in the intestines that indicate something is stuck. However, X-rays catch intestinal obstructions only about 55% to 92% of the time, depending on the type of blockage. Ultrasound is more reliable, with studies reporting 85% to 100% sensitivity for detecting mechanical obstructions. Your vet may use one or both.
Linear foreign bodies (string and thread) are notoriously hard to spot on X-rays, but they create a distinctive “bunching” pattern in the intestines that an experienced vet can recognize. Your vet will also check under your cat’s tongue, since string often loops around the base of the tongue before trailing into the digestive tract.
Treatment and Cost
Urinary blockages are treated by passing a catheter to relieve the obstruction and flush out the urethra. Your cat will typically need to stay in the hospital for 2 to 3 days on IV fluids while kidney function and electrolytes stabilize. Male cats that experience repeated urinary blockages may need a surgical procedure called a perineal urethrostomy, which widens the urethral opening permanently. That surgery runs roughly $1,500 to $3,000.
Intestinal blockages almost always require surgery. The surgeon opens the abdomen, locates the foreign object, and removes it through an incision in the intestinal wall. If the blockage has cut off blood supply to a section of intestine, that damaged portion may need to be removed entirely. Intestinal blockage surgery in cats costs $1,500 to $12,000 or more, depending on the complexity. Linear foreign bodies from string-like materials tend toward the higher end ($3,000 to $12,000) because the bunched intestines require more delicate repair. Partial blockages that respond to supportive care without surgery typically cost $1,500 to $7,000.
What to Do Right Now
If your cat is repeatedly vomiting and won’t eat, or if your cat is straining in the litter box with little or no urine output, don’t wait to see if it improves on its own. Both situations warrant a vet visit the same day. For urinary blockages in particular, a veterinary emergency room is the best option if one is available in your area, since they’re equipped for the intensive monitoring these cases need.
Do not try to give your cat a laxative. Stimulant laxatives are specifically contraindicated when a bowel obstruction is present, as they force the intestines to contract against an object they can’t move past, increasing the risk of rupture. Don’t try to pull out any string or thread you can see. Don’t offer food if your cat has been vomiting repeatedly, as this can worsen the situation and complicate anesthesia if surgery is needed. The single most useful thing you can do at home is recognize the signs early and get your cat to a vet quickly.