# Cat Trembling or Vomiting After Spay: What's Normal? Mild trembling and one or two episodes of vomiting in the first 12 to 24 hours after a spay are usually related to anesthesia wearing off and can be normal. Cat trembling after spay becomes a concern when it comes with heavy bleeding, repeated vomiting, a swollen or hot incision, or a cat who will not eat or drink. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Shivering, wobbling, and sleepiness are common as anesthesia wears off, and most cats improve over the first day. - One or two vomits in the first several hours can happen from anesthesia and motion, but repeated vomiting is not normal. - A small amount of redness at the incision is expected, but active bleeding, swelling, or discharge is not. - Most cats should start eating and drinking within 24 hours. A cat who refuses food or water for a full day needs a call to your vet. - Call your veterinarian the same day for repeated vomiting, no eating, or a cat who seems painful. Go to an emergency clinic now for heavy bleeding, trouble breathing, collapse, or a pale gum color. ## What Trembling and Vomiting After a Spay Usually Look Like A spay (ovariohysterectomy) removes the ovaries and uterus through a small abdominal incision. Your cat was under general anesthesia, and her body is clearing those drugs while she recovers. Trembling is one of the most common things owners notice. It often looks like a fine shiver through the whole body, or a slight quiver in the legs when she tries to stand. Some cats paddle their feet, twitch their whiskers, or hold their head low. These movements are usually the nervous system waking back up. Vomiting, if it happens at all, is typically a single episode of clear fluid or a small amount of foam. It often occurs in the car on the way home or in the first few hours while your cat is still groggy. Normal recovery also includes: - Sleepiness and a wobbly walk for the first 12 to 24 hours - Dilated pupils and a slightly glazed look - Hiding, quiet behavior, and less interest in play - A small amount of pink or red at the incision edge - A soft belly that is tender to touch but not hard or bloated Kittens may show specific pain behaviors after surgery, including a lowered head position, eyes partially closed, and reduced attention to surroundings. These behaviors were longer before pain relief than after in one study of kittens following spay surgery [1]. That tells you a quiet, hunched, half-closed-eye posture can be a sign of discomfort, not just sleepiness. ## Main Causes of Trembling and Vomiting After a Spay ### Anesthesia Recovery General anesthesia affects the whole body. As it wears off, cats can shiver, tremble, and act unsteady. This is the most common and most harmless cause of trembling in the first day. ### Nausea From Anesthesia or Pain Medication Nausea is a known side effect of some sedatives and opioids used around surgery. In a controlled trial, a sedative drug (xylazine) raised pain scores on two feline pain scales, which shows that nausea and drug effects can mimic or overlap with pain behaviors [2]. In plain terms, a nauseated cat can look like a painful cat, and both can look like a trembling cat. ### Pain Surgical pain is real, even with good pain control. Pain behaviors in cats include a lowered head, partially closed eyes, and not paying attention to surroundings [1]. If your cat trembles when she moves or when you touch her belly, pain is a reasonable concern. ### Bleeding Into the Abdomen This is uncommon but serious. In a large study of 9,513 cats spayed in high-volume clinics, 10.6% had some intraoperative bleeding and 0.8% had a major intraoperative bleed. Twenty-eight cats (0.3%) needed an autotransfusion, and 26 of those received it after surgery [3]. Cats in heat, in late pregnancy, or recently pregnant had a higher proportion of abdominal bleeding [3]. Bleeding can cause weakness, trembling, pale gums, and a swollen belly. ### Infection or Incision Problems An infected or opening incision causes pain, swelling, redness, discharge, and sometimes fever. Trembling from pain or fever can follow. ### Other Causes Unrelated to Surgery Vomiting has many causes beyond surgery, including digestive disease, kidney or liver problems, pancreatitis, parasites, infections, drugs, foreign objects, and tumors [4]. If your cat was vomiting before the spay or has a long history of vomiting, the surgery may not be the whole story. | Cause | Typical clues | How urgent | |---|---|---| | Anesthesia recovery | Fine shivering, wobbling, sleepiness, first 12 to 24 hours | Monitor at home | | Nausea from drugs | One or two vomits, drooling, lip licking, first few hours | Call if it continues past 24 hours | | Pain | Hunched posture, lowered head, half-closed eyes, flinching when touched [1] | Call the same day | | Bleeding into the abdomen | Pale gums, weakness, swollen belly, trembling that worsens [3] | Emergency now | | Infection or incision problem | Redness, swelling, pus, bad smell, fever | Call the same day | | Unrelated illness | Vomiting before surgery, weight loss, long-term vomiting [4] | Routine visit or same day if severe | ## Red Flags That Mean Emergency Care Some signs mean you should stop watching and go to a veterinary emergency clinic right away. - Heavy bleeding from the incision that soaks through a bandage or drips - Pale, white, or blue gums - Trouble breathing, open-mouth breathing, or loud breathing - Collapse, inability to stand, or extreme weakness - A belly that looks swollen, tight, or larger than before surgery - Repeated vomiting, especially vomit with blood or a coffee-ground look - Straining to urinate or no urine for many hours - A body temperature that feels very cold or very hot to the touch - Seizure activity or continuous, violent trembling Bleeding into the abdomen is rare but can be life threatening, and it can appear after the cat goes home [3]. If your cat was in heat or recently pregnant before the spay, keep a closer watch, because those cats had more abdominal bleeding in one large study [3]. ## What You Can Safely Do at Home Your job in the first 24 hours is quiet monitoring, not fixing. - Keep her in a small, warm, quiet room away from kids, dogs, and other cats. - Offer a small amount of water first. If she keeps it down, offer a small meal of her normal food. - Do not force food or water into her mouth. - Do not give human pain medications. Many are toxic to cats, and the dose must be calculated by your veterinarian based on her weight and health. - Check the incision twice a day with clean hands. Look for redness, swelling, discharge, or opening. - Use a litter box with low sides or shredded paper so she does not have to climb or get litter in the incision. - Keep the cone or surgical suit on if your vet sent one home. Licking can open an incision fast. - Take her temperature only if your vet asked you to and showed you how. A rectal thermometer can injure a healing incision area if used roughly. - Write down the time of each vomit, each meal, and each pee or poop. This log helps your vet decide fast. If your cat is trembling and also vomiting, that combination deserves a closer look. Our guide on [cat shaking and vomiting](/knowledge/veterinary-medicine/vet-visit-decisions/cat-shaking-and-vomiting) walks through when that pair of signs needs a same-day call. If the trembling happens without vomiting and you are not sure whether it is serious, see [cat shaking or trembling: is it an emergency](/knowledge/veterinary-medicine/vet-visit-decisions/cat-shaking-when-emergency). ## What Your Veterinarian Will Check When you call or bring your cat in, your vet will start with a full physical exam. - Gum color and capillary refill time to check circulation - Heart rate, pulse strength, and breathing rate - Body temperature - Abdominal palpation to feel for swelling, fluid, or a hard, painful belly - Incision inspection for redness, discharge, or separation - Hydration check by skin tent and gum moisture - Neurologic check for tremor type, balance, and pupil response Testing depends on what your vet finds. Common options include: - Blood work (complete blood count and chemistry) to look for infection, anemia, dehydration, or organ problems - A belly ultrasound or X-ray if bleeding, fluid, or a foreign object is suspected - A urine sample if urinary blockage or kidney issues are possible - A recheck of pain level using a validated feline pain scale Pain scoring in cats is not always simple. Nausea and opioid side effects can change pain scores on the Feline Grimace Scale and the Glasgow Composite Measure Pain Scale, so your vet may treat nausea and pain together and then reassess [2]. If your cat is trembling, your vet may also check for low blood sugar, low calcium, or a reaction to a specific drug. Treatment depends on the cause. Options include warming, fluids under the skin or in a vein, anti-nausea medication, additional pain relief, antibiotics if infection is present, or surgery to stop bleeding or repair the incision. ## Preventing Problems and Monitoring Recovery Good aftercare lowers the risk of complications. - Follow your discharge instructions exactly, including medication timing. - Keep the cone on for the full number of days your vet recommends. - Limit jumping, stairs, and rough play for the recovery period your vet sets. - Check the incision daily and take a photo each day so you can compare. - Offer small, frequent meals instead of one large meal. - Keep other pets separated until your cat is steady on her feet. - Call your vet if anything changes, even if it seems small. Vomiting that starts after eating or drinking too fast is a separate issue from surgery. If your cat bolts her food after recovery and vomits soon after, see [cat vomiting after eating too fast](/knowledge/veterinary-medicine/vet-visit-decisions/cat-vomiting-after-eating-too-fast). If she vomits right after drinking water, that pattern is covered in [cat vomiting after drinking water](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-vomiting-after-drinking-water). A single vomit with a cat who then acts normal is often a watch-and-wait situation. Our article on [cat vomiting once and acting normal](/knowledge/veterinary-medicine/vet-visit-decisions/cat-vomiting-once-acting-normal) explains how to track it. ## Limitations and When to Contact a Veterinarian This article cannot tell you what is happening inside your specific cat. Only a veterinarian who examines her can do that. **Contact your veterinarian the same day if:** - Your cat vomits more than once or vomits for more than 12 hours - She has not eaten or drunk anything for 24 hours - She trembles constantly or trembles more when touched - The incision looks red, swollen, warm, or has any discharge - She has not peed within 24 hours of coming home - She seems painful despite her medication **Go to an emergency clinic now if:** - Bleeding from the incision will not stop - Her gums are pale, white, or blue - She collapses, cannot stand, or breathes with an open mouth - Her belly is swollen, hard, or clearly larger than before - She has a seizure or violent, continuous trembling - She vomits blood or material that looks like coffee grounds **Schedule a routine recheck if:** - She is eating and drinking but still quieter than usual after 48 hours - The incision looks healed but she has a small lump - She has soft stool or mild appetite changes that last more than two days ## Frequently Asked Questions ### How long does trembling last after a spay? Most post-anesthesia trembling fades within 12 to 24 hours as the drugs clear. If trembling continues past 24 hours, gets worse, or comes with vomiting, pain postures, or a swollen belly, call your veterinarian. ### Is it normal for my cat to vomit after a spay? One vomit in the first few hours can be normal from anesthesia and the car ride. Repeated vomiting, vomiting past 24 hours, or vomiting with blood is not normal and needs a same-day call. ### Why is my cat not eating after a spay? Nausea, sleepiness, and pain can all suppress appetite on the first day. Offer small amounts of her normal food and water, and call your vet if she has eaten nothing by 24 hours after surgery. ### Can I give my cat anything for pain or nausea at home? No. Do not give human medications, because many are toxic to cats and the correct dose must be calculated by your veterinarian from your cat's weight and health. Call your vet if you think she is painful or nauseated. ### What does a normal incision look like after a spay? A normal incision is a thin line with a small amount of pink or red at the edges and no active bleeding. Swelling, spreading, pus, a bad smell, or a hot, painful area are signs to call your vet. ## Related Articles - [Cat Shaking or Trembling: Is It an Emergency?](/knowledge/veterinary-medicine/vet-visit-decisions/cat-shaking-when-emergency) - [Cat Shaking and Vomiting: When to Rush to the Vet](/knowledge/veterinary-medicine/vet-visit-decisions/cat-shaking-and-vomiting) - [Cat Vomiting After Eating Too Fast: When to Slow Down and When to Call](/knowledge/veterinary-medicine/vet-visit-decisions/cat-vomiting-after-eating-too-fast) - [Cat Vomiting After Drinking Water: Causes and When to Worry](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-vomiting-after-drinking-water) - [Cat Vomiting Once and Acting Normal: When to Monitor and When to Call](/knowledge/veterinary-medicine/vet-visit-decisions/cat-vomiting-once-acting-normal) - [Cat Vomiting: When to Worry and What to Do](/knowledge/veterinary-medicine/online-vet-and-care-costs/cat-vomiting-when-to-worry-what-to-do) - [Cat Wobbly After Anesthesia or Spay: What's Normal?](/knowledge/veterinary-medicine/vet-visit-decisions/cat-wobbly-after-anesthesia-spay) - [Why Is My Kitten Shaking or Trembling?](/knowledge/veterinary-medicine/symptom-guides/kitten-shaking-trembling) - [Cat Spay Incision After One Week: Normal vs. Warning Signs](/knowledge/veterinary-medicine/preventive-and-routine-care/cat-spay-incision-after-one-week) ## References 1. [Characterization of pain behaviors in kittens following ovariohysterectomy using video assessment](https://pubmed.ncbi.nlm.nih.gov/40295546/). Scientific reports, 2025. 2. [Influence of drug-induced nausea and opioid-associated behavioural alterations on pain scores in nonpainful cats: a prospective, randomised, experimental trial](https://pubmed.ncbi.nlm.nih.gov/42721642/). Veterinary anaesthesia and analgesia, 2026. 3. [Reproductive status and abnormal clinical signs after surgery are positively associated with hemoabdomen and autotransfusion in cats after ovariohysterectomy](https://pubmed.ncbi.nlm.nih.gov/41061732/). Journal of the American Veterinary Medical Association, 2026. 4. [Vomiting in Cats - Cat Owners](https://www.merckvetmanual.com/cat-owners/digestive-disorders-of-cats/vomiting-in-cats). Merck Veterinary Manual. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [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)