10 Causes of Cat Vomiting and Diarrhea

Cat vomiting and diarrhea most often result from a sudden diet change, eating something they shouldn’t, intestinal parasites, or an infection, though chronic conditions like inflammatory bowel disease, kidney disease, and hyperthyroidism can also be responsible. A single episode in an otherwise bright, hungry cat is usually less concerning than repeated bouts, blood, or lethargy. Because cats are experts at hiding illness, digestive upset is often one of the first visible clues that something isn’t right. Losing fluid from both ends at once can also dehydrate a cat faster than many owners expect. At Levan Road Veterinary Hospital in Livonia, MI, we regularly help cat owners figure out whether a stomach upset will pass on its own or needs medical attention. This article walks through the signs to watch for, ten common causes, what to do about a possible poisoning, how to support your cat while they recover, and when a call to your veterinarian can’t wait.

Signs of Diarrhea in Cats

Healthy cat stool is brown, formed, and firm enough to hold its shape. Diarrhea is any stool that’s noticeably softer, looser, or more frequent than your cat’s usual pattern.

What to Look For in the Litter Box

Because many cats bury their waste, diarrhea can go unnoticed for a day or two. Scooping daily gives you the best chance of spotting changes early. Signs of diarrhea in cats include:

• Soft, mushy, or watery stool
• More frequent trips to the litter box
• Straining or urgency, sometimes with very small amounts of stool
• Mucus or bright red blood in or on the stool
• Black, tarry stool, which can indicate bleeding higher in the digestive tract
• Accidents outside the litter box
• Stool stuck to the fur around the tail or hindquarters
• An unusually strong odor

Small Bowel vs. Large Bowel Diarrhea

Veterinarians often classify diarrhea by where it starts. Small intestinal diarrhea tends to produce larger volumes of stool and may come with weight loss. Large intestinal diarrhea (colitis) usually means frequent, small amounts with mucus, fresh blood, and straining. Noting which pattern you see helps your veterinarian narrow down the cause, especially when cat vomiting and diarrhea show up together.

Signs of Vomiting in Cats

Vomiting is an active process in which the abdomen contracts forcefully to push contents out of the stomach or upper intestine. It’s different from regurgitation, which is a passive return of undigested food, usually soon after eating and without abdominal heaving.

Recognizing Nausea and Vomiting

Many cats show subtle warning signs before they vomit. You may notice drooling, lip licking, repeated swallowing, crouching with the head low, or loud vocalizing. During vomiting, you’ll often see visible heaving of the belly. The material brought up may include food, clear or white foam, yellow bile, hair, or grass.

Is Occasional Vomiting Normal?

Many people assume regular vomiting is just “something cats do,” but frequent vomiting isn’t normal, even when it’s only hairballs. Cats that vomit more than once or twice a month deserve a veterinary evaluation, since chronic vomiting can be an early sign of intestinal disease or other health problems. Vomit that contains blood, looks like coffee grounds, or smells like stool is always a reason to call your veterinarian promptly. The same goes for any vomiting that happens alongside loose stool, since cat vomiting and diarrhea together drain fluids and electrolytes quickly.

What to Do if Your Cat Has Diarrhea and Is Vomiting

If you notice cat vomiting and diarrhea at the same time, the first step is to observe carefully and contact your veterinarian. Having both symptoms together raises the risk of dehydration, so it’s wise to get professional input early rather than waiting several days.

Gather Useful Information

Before you call, try to note the details your veterinary team will ask about. How many times has your cat vomited or had diarrhea, and over what time span? What did the vomit and stool look like? Is your cat still eating and drinking? Have you changed foods, added a new pet, or noticed anything chewed or missing around the house? A quick photo of the vomit or stool can be surprisingly helpful. If you share your home with more than one cat, try to confirm which one is sick, since cat vomiting and diarrhea in multiple pets at once may point to a shared cause like food, parasites, or an infection.

What Not to Do

Avoid giving any human medication, including common anti-diarrheal or stomach products. Several over-the-counter drugs that are safe for people are dangerous or even fatal for cats. Don’t try to make your cat vomit, and don’t withhold food or water unless your veterinarian specifically recommends it. Cats that go without eating for even a few days can develop a serious liver condition called hepatic lipidosis.

Causes of Diarrhea and Vomiting in Cats

Many different conditions can upset a cat’s digestive system. Some cause brief, mild illness, while others lead to chronic cat vomiting and diarrhea that comes and goes for weeks or months. Here are ten of the most common causes veterinarians see.

1. Sudden Diet Changes

Switching foods too quickly can upset the balance of bacteria in the gut and trigger both symptoms.

2. Dietary Indiscretion

Cats that raid the trash, eat table scraps, or snack on spoiled food often end up with an upset stomach.

3. Hairballs

Hairballs primarily cause vomiting, but a heavy buildup of hair can also irritate the intestines.

4. Intestinal Parasites

Roundworms, hookworms, Giardia, and coccidia are common culprits, especially in kittens and outdoor cats.

5. Viral and Bacterial Infections

Feline panleukopenia, coronavirus, Salmonella, and other infections can cause severe cat vomiting and diarrhea, particularly in unvaccinated cats.

6. Food Allergies or Intolerances

Sensitivity to certain proteins or ingredients can produce recurring cat vomiting and diarrhea, sometimes along with itchy skin.

7. Inflammatory Bowel Disease

IBD causes ongoing inflammation of the gut lining and is a frequent reason for chronic symptoms in middle-aged and older cats. Intestinal lymphoma can look similar and requires testing to tell apart.

8. Foreign Objects

String, hair ties, ribbon, and small toys can cause a dangerous intestinal blockage.

9. Organ and Hormone Disorders

Kidney disease, liver disease, pancreatitis, and hyperthyroidism commonly lead to vomiting, diarrhea, or both.

10. Toxins and Stress

Poisonous plants, chemicals, and medications can cause sudden illness. Stress from moving, travel, or household changes may also trigger digestive upset in sensitive cats.

What if My Cat Has Been Poisoned?

If you suspect your cat has been poisoned, contact your veterinarian or an emergency animal hospital immediately, even if your cat seems fine right now. Some toxins cause delayed damage to the kidneys or liver, and early treatment greatly improves the outlook.

Common Household Toxins for Cats

Cats are curious and groom themselves constantly, which means they can ingest toxins just by walking through a spill or brushing against a plant. Common dangers include:

• Lilies of any kind, including Easter, tiger, and daylilies, where even pollen can cause kidney failure
• Human pain relievers such as acetaminophen and ibuprofen
• Antifreeze (ethylene glycol)
• Dog flea and tick products containing permethrin
• Essential oils and liquid potpourri
• Rodent baits and insecticides
• Household cleaners and garden chemicals

Signs of Poisoning and How to Respond

Poisoning can cause sudden cat vomiting and diarrhea along with drooling, tremors, seizures, wobbliness, difficulty breathing, or collapse. Bring the product packaging or a piece of the plant with you if you can do so safely. Pet poison hotlines, such as the ASPCA Animal Poison Control Center and Pet Poison Helpline, can also offer guidance, though a consultation fee may apply. Never attempt to induce vomiting at home unless a veterinarian instructs you to.

How to Take Care of Your Ill Cat

Supporting your cat at home is about comfort, observation, and following your veterinarian’s plan closely. Your veterinary team will tailor recommendations to your cat’s diagnosis, so their instructions always come first.

Create a Calm Recovery Space

Sick cats appreciate a quiet, warm room away from busy household traffic, other pets, and young children. Place fresh water, food, a clean litter box, and a soft bed within easy reach. If your cat has diarrhea, scoop and refresh the litter box more often, and gently check that your cat’s fur stays clean.

Follow Your Veterinarian’s Plan

Give any prescribed medications or recommended diets exactly as directed, and finish the full course even if your cat seems better. If you have trouble giving medication, ask your veterinary team for tips or alternative forms. Don’t introduce new foods, treats, or supplements without checking first.

Track Your Cat’s Progress

Keep a simple log of meals, water intake, litter box visits, episodes of cat vomiting and diarrhea, and energy level. This record helps your veterinarian judge how well treatment is working and spot any setbacks early. Call right away if symptoms return or worsen.

When to Call Your Vet About Cat Vomiting and Diarrhea

Call your veterinarian the same day if cat vomiting and diarrhea last longer than 24 hours, happen more than a few times, or occur in a kitten, senior cat, or cat with an existing health condition. Seek emergency care for blood in the vomit or stool, repeated vomiting with no ability to keep water down, lethargy, pale gums, a painful belly, straining without producing stool, or any suspicion of toxin exposure or a swallowed object. Cats that stop eating for more than a day also need prompt attention.

At Levan Road Veterinary Hospital, our team takes digestive symptoms seriously and works to pinpoint the cause quickly, whether that means a physical exam, fecal testing, bloodwork, or imaging. We proudly care for cats throughout Livonia, MI, and nearby communities. If your cat is dealing with vomiting, diarrhea, or both, call Levan Road Veterinary Hospital at (734) 464-6281 to schedule an appointment. Getting answers early helps your cat feel better sooner.