A cat with a gastric ulcer rarely vomits blood on day one. It eats two-thirds of its usual portion, drops 200 to 400 g over 3 to 6 weeks, grinds its teeth after meals, and vomits 2 to 4 times a week. Those quiet signs are why ulcers are found late: the stomach lining can be eroded for 10 to 14 days before anyone books an exam. Three questions decide the plan — which sign group the cat shows, what eroded the lining, and how long to wait before endoscopy.
Why the stomach lining fails
The stomach defends itself with mucus, bicarbonate, and steady blood flow. Any insult that removes one of the three starts an ulcer within hours, not months. Pain relievers of the nonsteroidal class cut prostaglandin production, so mucus thickness and mucosal blood flow fall within 24 to 72 hours of daily use; the risk climbs when a steroid is given at the same time. Physiological stress works faster: shock, sepsis, pancreatitis, a 3-day hospital stay, or major surgery can produce shallow erosions in 24 to 48 hours. Infiltrative disease — lymphoma, mast cell tumor, adenocarcinoma — erodes the wall from beneath, which is why a cat that fails 4 weeks of acid suppression needs a biopsy rather than a stronger tablet. Chronic kidney disease adds uremic irritation, and liver disease removes the bile buffer that normally protects the antrum.
Sign group 1: the eating pattern
Early ulcers change appetite before they change weight. A cat that used to finish 85 g of wet food in one sitting eats 40 to 50 g, walks away, and returns 20 minutes later. Vomiting is intermittent rather than daily: 2 to 4 episodes a week, usually 30 to 90 minutes after eating, with food that looks barely digested. Some cats vomit once and then eat again right away, which owners read as greed rather than pain. Weigh the cat weekly on the same scale at the same time of day; a slide from 5.0 kg to 4.75 kg across 30 days is enough to justify bloodwork. A cat that vomits and also strains in the litter box needs the urinary check first, because a blocked tom can look exactly like a gut case — see urinary blockage signs.
Sign group 2: blood loss, visible and hidden
Bleeding is usually slow rather than dramatic. Melena — black, tarry stool that is 2 to 3 times stickier than normal — appears once 60 to 100 mL of blood has been lost into the upper tract, and owners miss it against dark litter. Hidden loss shows up as numbers instead: packed cell volume sliding from 35 to 26 over 3 weeks, or a regenerative response with 2 to 4 nucleated red cells per 100 white cells. Gums shift from pink to pale peach at around 20. Hematemesis, coffee-ground vomit, or a PCV under 20 means the cat is losing volume now: hospital today, not a recheck in 7 days.
Sign group 3: pain behavior
Cats guard the abdomen instead of crying. Look for a hunched posture held 20 to 40 minutes after meals, lip smacking every 5 to 10 seconds for a minute or two, teeth grinding audible from 1 m away, and refusal to lie on the right side. Some press the belly against a wall or the floor for 10 minutes at a time. A cat that stops jumping onto a 60 cm counter, or lands stiffly, is often showing gastric or pancreatic pain rather than arthritis. Any of these signs plus vomiting 6 or more times in 24 hours is a same-day visit.
The numbers that separate ulcer from upset stomach
| Test | Value that changes the plan | Repeat in |
|---|---|---|
| PCV and total solids | PCV under 26, or a fall of 5 points in 21 days | 7 days |
| BUN and creatinine | BUN over 40 mg/dL with urine specific gravity under 1.035 | 14 days |
| Fecal occult blood | Positive on 2 of 3 samples | 3 days |
| Abdominal ultrasound | Wall thickness over 4 mm, or loss of the 5-layer pattern | 30 days |
| Endoscopy with biopsy | Still vomiting 2 or more times a week after 14 days of treatment | 6 to 8 weeks |
Two of these numbers matter more than the rest. A PCV that falls 5 points in 3 weeks, or a BUN that rises while urine stays dilute, moves the case from mild irritation to systemic disease. The table is also the reason not to repeat a full panel every 3 days: each row has its own clock.
Endoscopy: the timing rules
A scope is not the first test. Start with bloodwork, urine specific gravity, fecal occult blood, retrovirus status, and ultrasound; that sequence settles most cases in 3 to 5 days for a fraction of the cost of a scope, which is where the cost of a workup becomes relevant. Scope within 24 to 48 hours when there is hematemesis, melena with a PCV under 26, or vomiting more than 6 times in 24 hours. Scope electively after 10 to 14 days of acid suppression if vomiting continues at 2 or more episodes a week. Fast the cat 12 to 18 hours, never past 24, and take 6 to 8 biopsies from body and antrum even when the surface looks normal, because feline ulcers can hide under intact mucosa. A single crater wider than 1 cm in a cat over 10 should be sampled for neoplasia in the same session.
Four steps after the diagnosis
- Stop every nonsteroidal pain reliever on day 1 and ask for a different class if pain control is still needed.
- Run acid suppression for 4 to 6 weeks, with a weight and appetite check at day 14 and day 42.
- Feed 4 to 6 small meals a day and keep the same food, so a 3-day food trial does not confuse the picture.
- Recheck PCV and BUN at 14 days, and repeat the scope at 6 to 8 weeks only if signs persist.
Cats with a healed ulcer still relapse if the trigger stays: monthly nonsteroidal use, untreated kidney disease, or an unbiopsied mass. Keep the 30-day weight log going and bring it to every visit.
Terms mentioned in this article
Frequently asked
Can a cat have a gastric ulcer without vomiting?
Yes, and that is the common early case. Appetite falls first: a cat eats 40 to 50 g instead of 85 g, loses 200 to 400 g in a month, and grinds its teeth after meals. Vomiting may only appear at 2 to 4 episodes a week, or not at all when the ulcer is small. Weight loss plus a change in eating posture is reason enough for bloodwork and an ultrasound.
How long can a cat wait before endoscopy?
If there is no hematemesis and the packed cell volume is stable above 26, waiting 10 to 14 days on acid suppression is reasonable. With coffee-ground vomit, melena, or a PCV under 26, the scope moves to 24 to 48 hours. Vomiting more than 6 times in 24 hours is a same-day hospital visit regardless of the other numbers.
Do ulcers come back after treatment?
They do when the trigger is still there. Monthly nonsteroidal use, untreated kidney disease, or an infiltrative tumor that was never biopsied will reopen the same spot within weeks. A healed cat should still be weighed every 2 weeks for the first 2 months, and any return of vomiting at 2 or more episodes a week means a repeat look rather than another 4-week course.