# Why Is My Cat Throwing Up in or Near the Litter Box? Vomiting right in or beside the litter box usually means something about that visit upset your cat's stomach or caused pain. The most common reasons are constipation or straining, nausea that peaks during or after elimination, and pain from the lower urinary or intestinal tract. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Vomiting is an active, forceful process with retching and belly contractions, while regurgitation is passive and produces undigested, tube-shaped food [1]. - Cats often vomit near the box because straining to poop or pee triggers nausea or pain, especially with constipation. - A single vomit after a normal box visit is often minor, but repeated vomiting, blood, or a cat that cannot poop or pee needs a vet. - Never give human anti-nausea or pain medicine to a cat without veterinary direction. - Track how often your cat vomits, what it looks like, and whether it happens only around box visits, because that pattern helps your vet. ## What the Sign Looks Like and What Is Normal Vomiting in cats is the forceful ejection of stomach and upper small intestine contents through the mouth. It is normally preceded by excessive salivation, repeated swallowing, retching, and forceful contractions of the abdominal muscles and the diaphragm [1]. That is different from regurgitation, which is a passive motion with no effort or abdominal contraction. Regurgitated food tends to be undigested and may have a cylindrical shape reflecting the shape of the esophagus [1]. So the first question is whether your cat is truly vomiting or just bringing up food. True vomiting involves heaving, drooling, and a body-wide effort. If your cat opens its mouth and food simply falls out, that is more likely regurgitation. Normal cats vomit occasionally. A single episode of food or hair, followed by a cat that eats, drinks, and plays normally, is usually not an emergency. What matters is the pattern. Vomiting that happens every time your cat uses the litter box, or that comes with straining, is a signal worth investigating. ## Why Your Cat Is Throwing Up in the Litter Box The litter box is where cats strain, squat, and sometimes feel discomfort. That makes it a common place for nausea or pain to tip into vomiting. Here are the main causes. ### Constipation and Straining Constipation is one of the most common reasons a cat vomits around box visits. When a cat strains hard to pass hard stool, the effort can trigger retching and vomiting. You may notice your cat going in and out of the box, squatting for a long time, crying, and then vomiting nearby. This is the classic "cat straining then vomiting" pattern. Long-haired cats, older cats, cats that do not drink enough water, and cats eating a low-fiber or dry-only diet are more prone to constipation. If your cat has not passed stool in a day or more and is vomiting, call your vet. ### Nausea That Peaks During Elimination Some cats feel nauseated much of the day, and the physical effort of eliminating pushes them over the edge. This is why you might see a cat vomit after using the litter box even when the stool looks normal. The box visit is not the cause, it is the trigger that reveals an underlying stomach or intestinal problem. ### Pain From the Urinary Tract Cats with bladder inflammation, crystals, or stones often associate the litter box with pain. They may squat, strain, produce little or no urine, and then vomit from the discomfort. This is especially serious in male cats, because a blocked urethra is a life-threatening emergency. If your cat is straining to urinate and vomiting, treat it as an emergency. ### Pain From the Intestines or Other Organs Vomiting can be caused by digestive system disease, kidney or liver failure, pancreatitis, or nervous system disorders. Other causes include poisons, insect stings or snake bites, internal parasites (including heartworm disease), infections, inflammation, drugs, ingestion of a foreign object, food allergy, and tumors [1]. Some of these conditions cause pain that worsens when the cat bears down to eliminate. A foreign object is a real risk. One report described a cat with five days of vomiting and no appetite caused by a doughnut-shaped object stuck in the duodenum, which blocked the bile duct and required surgery [2]. That cat recovered, but the case shows how a swallowed object can cause vomiting that looks like a routine stomach upset. ### Hairballs and Hairball-Like Vomiting Frequent hairballs are not normal. See your veterinarian if your cat is having frequent hairballs or vomiting repeatedly, because something more serious than a hairball could be to blame [1]. If your cat brings up undigested food, that is a different sign worth reading about in [What Does It Mean When A Cat Throws Up Undigested Food](/knowledge/veterinary-medicine/nutrition/what-does-it-mean-when-a-cat-throws-up-undigested-food). ### Cause Table | Cause | Typical clues | How urgent | |---|---|---| | Constipation | Straining, hard small stools, long box visits, vomiting after straining | Same-day vet visit if no stool in 24 to 48 hours or repeated vomiting | | Nausea from stomach or intestinal disease | Vomiting after most box visits, drooling, lip licking, reduced appetite | Routine to same-day visit, depending on frequency | | Urinary blockage or bladder pain | Straining to urinate, little or no urine, crying, vomiting | Emergency now, especially in male cats | | Foreign object or obstruction | Vomiting, no appetite, painful belly, no stool | Emergency now | | Kidney or liver disease | Increased thirst and urination, weight loss, vomiting, poor coat | Same-day to routine visit | | Pancreatitis | Vomiting, belly pain, hunched posture, no appetite | Same-day visit | | Hairballs | Bringing up hair, frequent retching | Routine visit if frequent | ## Red Flags That Make It an Emergency Some signs mean you should stop reading and call an emergency clinic. - Your cat is straining to urinate and nothing or almost nothing comes out. This is a urethral obstruction until proven otherwise. - Your cat is vomiting repeatedly and cannot keep water down. - There is blood in the vomit, or the vomit looks like coffee grounds. - Your cat's belly is swollen, hard, or painful to touch. - Your cat is collapsed, weak, breathing fast, or has pale gums. - You know or suspect your cat ate a foreign object, poison, or human medication. - Your cat has not pooped in more than two days and is vomiting. If you suspect poisoning, call the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661. Have your cat's weight and the product name ready. ## Safe Things You Can Do at Home While Waiting Home care is about comfort and observation, not treatment. Do not give your cat human anti-nausea drugs, pain relievers, or laxatives. Many common human medicines are toxic to cats, and the dose depends on your cat's weight and health. Your veterinarian calculates any dose. What you can do: - Remove food for a short time only if your vet advises it. Do not withhold water. - Offer small amounts of water frequently to keep your cat hydrated. - Keep the litter box clean and easy to reach. A cat that is nauseated may avoid a dirty or hard-to-reach box. - Note the time of each vomit, what it contains, and whether it happened right after a box visit. - Check the box for stool and urine. Count the clumps and look at stool size and hardness. - Keep your cat indoors and away from garbage, string, toys, and human food. - Do not switch foods suddenly during a vomiting episode. If your cat is peeing outside the box instead of inside, that is a different problem with its own causes. Read [Why Is My Cat Peeing Outside the Litter Box?](/knowledge/veterinary-medicine/symptom-guides/cat-peeing-outside-litter-box) for that pattern. ## What Your Veterinarian Will Check and Test Your vet will start with a full history. They will ask how often your cat vomits, whether it happens around box visits, what the vomit looks like, and whether stool and urine output have changed. Bring a photo of the vomit and a note of the times if you can. The physical exam checks hydration, gum color, belly pain, and whether the bladder is large or the colon is full of hard stool. Your vet may also check for a foreign object or mass. Common tests include: - Blood work to check kidney and liver values, electrolytes, and blood cell counts. - A urine test to look for infection, crystals, or concentrated urine. - X-rays or ultrasound to look for constipation, foreign objects, stones, or organ changes. - Fecal testing for parasites. - Blood pressure and thyroid testing in older cats. Treatment depends on the cause. Constipation may need fluids, stool softeners, or a prescription diet. Nausea may need an antiemetic. One review found that maropitant reduced the risk of vomiting in cats compared with control in the studies analyzed [3]. Your vet will choose a drug and dose based on your cat's weight and health. If your cat is vomiting for many possible reasons and you want a broader overview, see [Why Is My Cat Vomiting? Common Causes and Red Flags](/knowledge/veterinary-medicine/symptom-guides/why-is-my-cat-vomiting). ## Prevention and Monitoring Prevention starts with the litter box itself. At least 10% of all cats develop elimination problems, and these can stem from conflict between cats, dislike of the box or litter, a past medical condition, or the box location [4]. A cat that avoids the box can develop a surface or location preference, so act quickly if you see avoidance [4]. Make the box cat-friendly. One study found that cats preferred litter boxes measuring at least 50 cm (about 20 inches) and clumping clay litter. A comfortable litter environment combining those two elements promoted normal urination and improved house-soiling and unhappy behaviors during elimination [5]. So a bigger box with clumping litter may help. Other prevention steps: - Keep one box per cat plus one extra, in quiet, easy-to-reach spots. - Scoop daily and wash the box regularly. - Keep water available in several places to support hydration and stool softness. - Feed a diet your vet recommends for your cat's age and condition. - Watch for changes in how long your cat spends in the box. Cats with chronic kidney disease can show increased urination frequency, longer elimination times, and less covering after elimination [6]. - Track your cat's normal routine. Healthy cats tend to follow regular daily patterns of feeding and litter box use, so a change in that pattern is a clue [7]. If your cat vomits after pooping and also brings up undigested food, compare that pattern with [Cat Throwing Up Food Undigested](/knowledge/veterinary-medicine/nutrition/cat-throwing-up-food-undigested) and [My Cat Is Throwing Up Undigested Food](/knowledge/veterinary-medicine/nutrition/my-cat-is-throwing-up-undigested-food). ## Limitations and When to Contact a Veterinarian This article cannot tell you what is wrong with your cat. Only a veterinarian who examines your cat can do that. Individual cases need a veterinarian, and the timing below is a guide, not a diagnosis. Contact an emergency clinic now if your cat is straining to urinate with little or no urine, vomiting repeatedly and cannot keep water down, has a painful or swollen belly, is collapsed or weak, or you suspect poisoning or a swallowed object. Contact your vet the same day if your cat has vomited more than two or three times in a day, has not pooped in 24 to 48 hours, is vomiting after every box visit, has blood in the vomit, or is eating and drinking less than normal. Schedule a routine visit if the vomiting is occasional but keeps happening around box visits, if your cat has frequent hairballs, or if you notice changes in litter box habits such as longer visits or less covering [6]. Bring notes on frequency, timing, and what the vomit looks like. ## Frequently Asked Questions ### Why does my cat vomit right after using the litter box? The physical effort of straining or squatting can trigger nausea and retching, especially when your cat is constipated or in pain. The box visit is often the trigger, not the cause. If it happens every time, your cat needs a vet exam. ### Is vomiting after pooping always a sign of constipation? No, but constipation is one of the most common reasons. Other causes include stomach or intestinal disease, urinary pain, and swallowed objects. Your vet can tell the difference with an exam and tests. ### Can straining to poop make a cat throw up? Yes. Hard straining raises pressure in the belly and can trigger the retching reflex. If your cat strains for a long time, cries, and then vomits, that pattern points toward constipation or another painful condition. ### Should I take away my cat's food when it vomits? Only if your veterinarian tells you to. Withholding food is not right for every case, and water should stay available. A vet can advise based on your cat's age, weight, and health. ### When should I worry about a cat vomiting near the litter box? Worry if the vomiting repeats, if your cat stops eating or drinking, if there is blood, or if your cat is straining to urinate or poop with little result. Any of those signs means a same-day or emergency vet visit. ## Related Articles - [Why Is My Cat Peeing Outside the Litter Box?](/knowledge/veterinary-medicine/symptom-guides/cat-peeing-outside-litter-box) - [Why Is My Cat Vomiting? Common Causes and Red Flags](/knowledge/veterinary-medicine/symptom-guides/why-is-my-cat-vomiting) - [What Does It Mean When A Cat Throws Up Undigested Food](/knowledge/veterinary-medicine/nutrition/what-does-it-mean-when-a-cat-throws-up-undigested-food) - [Cat Throwing Up Food Undigested](/knowledge/veterinary-medicine/nutrition/cat-throwing-up-food-undigested) - [My Cat Is Throwing Up Undigested Food](/knowledge/veterinary-medicine/nutrition/my-cat-is-throwing-up-undigested-food) - [Why Is My Cat Pooping Outside the Litter Box? Causes and Solutions](/knowledge/veterinary-medicine/anxiety-and-behavior-support/cat-pooping-outside-litter-box) - [Why Is My Kitten Throwing Up? Causes and When to Worry](/knowledge/veterinary-medicine/digestive-and-urinary-care/kitten-throwing-up-causes) - [How to Stop Your Cat Throwing Up: Causes and Next Steps](/knowledge/veterinary-medicine/digestive-and-urinary-care/stop-cat-throwing-up-causes) - [Cat Threw Up: What to Do and When to Call the Vet](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-threw-up-what-to-do) - [Toxoplasma gondii in Cats: Zoonotic Risk from Litter Box Exposure](/knowledge/parasites/pet-parasites/toxoplasmosis-cat-litter-reddit) ## References 1. [Vomiting in Cats - Cat Owners](https://www.merckvetmanual.com/cat-owners/digestive-disorders-of-cats/vomiting-in-cats). Merck Veterinary Manual. 2. [Rare case of extrahepatic biliary obstruction caused by a duodenal foreign body in a cat](https://pubmed.ncbi.nlm.nih.gov/40933839/). JFMS open reports, 2025. 3. [Receptor-Targeted Antiemetic Strategies in Cats: A Systematic Review and Intervention-Specific Meta-Analysis](https://pubmed.ncbi.nlm.nih.gov/42599757/). Veterinary medicine and science, 2026. 4. [Litter Box Problems](https://www.aspca.org/pet-care/cat-care/common-cat-behavior-issues/litter-box-problems). ASPCA Animal Poison Control Center. 5. [Litter box size and litter type preference and their associated behavioral changes in cats](https://pubmed.ncbi.nlm.nih.gov/40204471/). The Journal of veterinary medical science, 2025. 6. [Enhancing Detection of Feline Chronic Kidney Disease Through Smart Litter Box Monitoring](https://pubmed.ncbi.nlm.nih.gov/42121739/). Animals : an open access journal from MDPI, 2026. 7. [Characterising individual feeding and elimination behaviours in healthy cats using a connected smart feeder and litter box: a preliminary study](https://pubmed.ncbi.nlm.nih.gov/41482871/). Journal of feline medicine and surgery, 2026. ## Further Reading - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)