Why Do Cats Eat String and When a Swallowed Thread Becomes an Emergency

Why do cats eat string, and why does a habit that looks like play sometimes end in emergency surgery? A length of yarn or thread can slip past a cat’s teeth in seconds, and once swallowed it can injure the intestine over the hours that follow.

This guide explains what drives the habit, why string is so risky, the signs to watch for, how veterinarians diagnose and treat it, and when your cat needs care right away.

Why Do Cats Eat String and Other Thread-Like Objects?

Chewing string is common, and swallowing it is less so. The UC Davis School of Veterinary Medicine notes that cats often chew objects, but only some swallow them. Regularly eating non-food items is called pica.

Veterinary sources point to several causes. The Merck Veterinary Manual lists stress or anxiety, including changes in a cat’s relationships with people or other cats, and early weaning. UC Davis adds boredom and medical problems. Cornell University’s College of Veterinary Medicine says chewing fabric may be a comfort-seeking behavior or a way to play and investigate, and that kittens often chew while exploring. Most outgrow it, though some keep the habit for life.

Breed also matters. Merck and UC Davis both say Siamese, Burmese and related Oriental breeds are more likely to suck or chew wool and fabric, which suggests a genetic link. Merck adds that disease, especially digestive disease, should be ruled out first, so a cat that suddenly starts eating string needs an exam and not only a new toy.

Why Swallowed String Is Dangerous for a Cat

String is a linear foreign body, meaning a long, thin object and not a solid lump. The Merck manual’s page on gastrointestinal obstruction names string, yarn and dental floss as typical examples and says cats tend to swallow them while playing. Cats are more likely than dogs to develop an obstruction from this kind of object, and young cats are more likely than older cats to develop a foreign body obstruction.

The danger comes from how thread behaves inside the body. One end can catch at the base of the tongue while the rest travels on, and the intestine bunches up along the anchored line. Merck says linear foreign bodies cause more damage to the bowel lining than other foreign bodies, sometimes over a long segment, and carry a higher risk of perforation, which means a hole in the bowel wall. Our guide to intestinal blockage in pets covers blockages of every kind, and string is one of the most urgent.

Where a Cat Ate Yarn, Thread or Floss

When a cat eats yarn, the source is usually an ordinary household item. Knitting baskets, sewing thread, dental floss and string from packages are all within reach of a curious cat, and Cornell warns that swallowed fabric can cause life-threatening obstructions. A trailing thread moves and invites batting, which is why it works like a toy. Kittens and young cats need the closest watch, since Merck says young cats are more likely to develop foreign body obstructions and Cornell notes that kittens explore by chewing.

Keep sewing supplies, floss and craft projects in closed containers, and pick up loose thread after mending. Cornell also lists electrical cords, twist ties, pins and needles as hazards for cats that chew, so the same caution applies to them.

Signs a Cat Swallowed String

Signs are often vague. The Merck manual says vomiting and loss of appetite are the most common, and less often owners see diarrhea, weight loss or lethargy. A cat may look normal for a while, especially when the thread is anchored under the tongue where you cannot see it.

Early Signs

Vomiting, refusing food and sleeping more than usual are what most owners notice first. Any of them in a cat with access to yarn or thread deserves attention, and our post on severe vomiting and diarrhea in pets explains when ongoing vomiting needs emergency care.

Signs of Serious Bowel Injury

Merck lists abdominal pain and, in the worst cases, shock or signs of septic shock when the bowel is badly damaged. A cat in that state is an emergency.

String in the Mouth

If you see string under your cat’s tongue or hanging from the mouth, do not pull it. Merck says a linear foreign body at the base of the tongue must never be pulled, because it may be embedded and pulling can cause perforation. A veterinarian cuts it free at the anchor point.

Comparing Where String Can Lodge

The three locations below can overlap, and a cat may have more than one at once. The details come from the Merck manual.

Location	What Is Happening	What You May Notice
Base of the tongue	One end of the thread anchors here while the rest travels on.	Often nothing visible, which is why veterinarians check under the tongue.
Stomach and small intestine	The bowel bunches up along the anchored thread.	Vomiting, loss of appetite and lethargy.
Bowel wall	Damage can spread along a long segment and may end in perforation.	Abdominal pain and, in severe cases, shock.

How Is Swallowed String Diagnosed?

Your veterinarian starts with history, so mention any string, yarn, floss or missing sewing supplies. The exam includes the mouth, because Merck says linear foreign bodies can anchor at the base of the tongue.

Imaging comes next. Merck says X-rays can show intestinal bunching along with gas or fluid-filled loops, although those changes are not specific to string. Ultrasound can also show foreign bodies, and contrast X-rays can help when an object does not show on a plain image. Endoscopy, a camera passed through the mouth, is not suitable for suspected linear foreign bodies because it cannot see beyond the upper intestine. Bloodwork often shows a raised white blood cell count along with electrolyte and acid-base changes, which help the team decide how to stabilize your cat. Thread is thin and hard to feel, so even a surgeon may not know its length until the abdomen is open.

How Is a Swallowed Thread Treated?

Treatment is surgical, and a veterinary team does all of it.

Stabilizing and Surgery

Merck says fluid, electrolyte and acid-base problems are corrected before surgery when possible. Gentle traction may free the string so it can come out through an incision in the stomach, while other cases need more than one incision along the intestine. Damaged or perforated bowel is removed and the healthy ends are rejoined. Some surgeons with the right equipment use laparoscopic-assisted removal, a smaller-incision approach, though the choice depends on the cat and the surgeon.

Recovery

Merck says the outlook is generally good when an obstruction is recognized and treated promptly. Risks rise with dehydration, shock, infection in the abdomen and very low protein levels in the blood, which is one more reason early treatment matters. Afterward the team continues fluids, electrolyte correction and nausea control, which is why overnight care matters, and our post on why some pet emergencies require overnight monitoring explains how it works.

When to Contact an Emergency Vet

If your cat swallowed string, or you suspect it, call veterinary emergency services right away, even if your cat looks fine. Merck links prompt treatment with good outcomes, and the complications it describes grow with dehydration and shock. Go immediately if you see string in the mouth, repeated vomiting, refusing food, belly pain or collapse. A missing spool or a loose thread you cannot account for counts as exposure.

Tangled thread tends to turn up late at night or on weekends, when your regular clinic is closed, and veterinary emergency services exist for that moment. Waiting makes the problem harder to treat, and our post on the impact of delayed emergency care explains why. If you are unsure which signs count, our list of pet emergency signs every owner should know can help.

Not every case is an emergency. A cat that chews string but has not swallowed any and is acting normally can be seen at a routine appointment to talk about the habit.

Safer Play for a Cat That Loves String

Cornell suggests hiding valuable and dangerous chewables, offering cat-safe rubber toys, and adding enrichment such as a cat condo or treat-dispensing toys. Merck recommends rewarding a desirable alternative behavior and avoiding punishment, which can raise anxiety. Dry or high-fiber food helps some cats. Put string-like toys away after supervised play. UC Davis notes that some cats begin pica when a new animal joins the household, and Merck lists changes in a cat’s relationships with people or other cats as a trigger, so watch more closely after any change at home.

Acting Fast When a Cat Swallows String

So why do cats eat string? Usually play, stress, boredom or an inherited habit, and sometimes a medical problem. Whatever the reason, a swallowed thread can injure the bowel quietly, and treated promptly it often has a good outcome. Close up the sewing basket, put away floss, and call right away if a thread goes missing.

At North MS Pet Emergency, we function as an overnight and weekend emergency vet for cats and dogs across North Mississippi, Northwest Alabama and Southwest Tennessee. Our team cares for pets with vomiting and digestive emergencies. If your cat has swallowed a string, or is showing the signs in this guide, do not wait. Contact us immediately for emergency evaluation and care.

Sources

Merck Veterinary Manual, Gastrointestinal Obstruction in Small Animals (2025). Professional veterinary reference published by Merck & Co., Inc. Supports why cats swallow linear objects, how string lodges and damages the bowel, diagnosis, surgical treatment and outlook.

Merck Veterinary Manual, Behavior Problems of Cats (2025). Professional veterinary reference published by Merck & Co., Inc. Supports the causes of pica, breed tendency, ruling out disease and behavior advice.

UC Davis School of Veterinary Medicine, Abnormal Eating Habits in Cats (2021). University veterinary school. Supports the definition of pica, its causes and breed tendency.

Cornell University College of Veterinary Medicine, Feline Behavior Problems: Destructive Behavior (2018). University veterinary college. Supports comfort and play chewing, the fabric obstruction warning and enrichment advice.

FAQs

Q: Why do cats eat string?

A: Veterinary sources point to play, stress, boredom, early weaning and an inherited tendency in Siamese, Burmese and related breeds. Medical problems can also be behind it, so a cat that suddenly starts eating thread needs a veterinary exam.

Q: My cat ate yarn but seems fine. Do I need to worry?

A: Yes. A cat can look normal while thread is anchored under the tongue or bunching the intestine, and you may not know how much was swallowed. Call an emergency vet, because Merck links prompt treatment with good outcomes.

Q: Should I pull string hanging from my cat’s mouth?

A: No. Merck says a linear foreign body at the base of the tongue must never be pulled, because pulling can cause perforation. Our intestinal blockage guide gives the same advice for string at the rear end. Go to an emergency vet right away.

Q: How do veterinarians find string inside a cat?

A: They check the mouth, then use X-rays, ultrasound and bloodwork. Merck says X-rays can show intestinal bunching, and endoscopy is not suitable for suspected linear foreign bodies.

Q: Do cats recover after surgery for swallowed string?

A: Many do. Merck says the outlook is generally good when an obstruction is recognized and treated promptly. Linear foreign bodies carry a higher risk of perforation than other foreign bodies, so early care matters.