Blood in vomit looks alarming and often is not, which is exactly why the numbers matter. Bright red streaks in foam usually mean bleeding in the mouth, esophagus, or stomach that happened minutes ago. Coffee-ground brown means blood sat in the stomach for 1 to 3 hours and was partly digested. The decision line most vets use: more than 2 blood vomits in 24 hours, or about 10 mL of estimated blood, or any blood with pale gums, and the cat goes in today.
Read the color before anything else
Three appearances cover most cases. Bright red, liquid, mixed with foam or food: fresh bleeding above the small intestine, often a stomach ulcer, a foreign body, or a clot from a biopsy site. Coffee-ground brown, granular, smelling of iron: blood that has been in contact with stomach acid for 1 to 3 hours, so the bleeding is slower and older. Dark red clots the size of a pea to a bean: usually swallowed blood from the nose or mouth, or a bleeding mass.
Pink-tinged foam with no solid material is the mildest pattern, and it often follows 3 to 5 hours of an empty stomach in a cat that vomited 4 or 5 times the night before. Irritation alone can produce a few red streaks, which is why 1 episode in a cat that then eats is not a same-day problem.
The 24-hour red line: more than 2
One blood vomit in 24 hours, in a cat that keeps eating and drinking, is a 24 to 48 hour watch with photographs. Two in 24 hours moves the cat to a same-week visit. More than 2 in 24 hours, or 2 within 6 hours, is today. The count matters more than the volume for small bleeds, because 3 small episodes suggest a source that keeps reopening, and a stomach that keeps bleeding loses about 1 mL per kg per hour once an ulcer is deep enough.
Add the time of the last meal: blood 30 to 90 minutes after eating points at the stomach or the esophagus, while blood 6 or more hours after eating points lower down. Write both times down; the pair narrows the source more than the color alone.
Estimate the volume in 10 mL units
Owners say a lot or a little, and vets cannot use either. Estimate in teaspoons: 1 teaspoon is 5 mL, 1 tablespoon is 15 mL, and a pool 2 cm across on a hard floor is about 10 mL. Photograph the vomit next to a coin or a ruler for scale, then scoop it into a clear bag and bring it. A total under 5 mL is a speck; 5 to 10 mL is a streak pattern; more than 10 mL in 24 hours, or any amount that keeps coming, is the number that changes triage.
Compare that with the cat's blood volume: roughly 60 to 70 mL per kg, so a 4 kg cat holds about 260 mL. Losing 10 mL is under 4% and is tolerated; losing 25 mL or more, roughly 10%, starts to show as a faster heart rate, and the gums go from pink to pale at around that point.
Where the blood can come from
Six sources cover nearly all cases: the mouth (a cut lip, a loose tooth, a bleeding gum), the esophagus (a foreign body such as a bone shard or a hair tie), the stomach (ulcer, gastritis, a mass), the small intestine (ulcer, parasite, intussusception), the lungs (coughed-up blood that is then swallowed), and the nose (blood swallowed at night and vomited in the morning). That last one surprises people: a cat with a 2-day nosebleed can vomit a coffee-ground material that has nothing to do with its stomach.
Look at the litter box before you call. Black, tarry stool that sticks to the scoop means digested blood from higher up, and it can appear 8 to 24 hours after a bleed that has already stopped.
Grade the episode
| Grade | Episodes in 24 h | Blood volume | Gums and behavior |
|---|---|---|---|
| 0 | 1 | under 5 mL, streaks | pink gums, eating |
| 1 | 2 | 5 to 10 mL | pink gums, picks at food |
| 2 | 3 to 5 | 10 to 25 mL | pale pink, quiet, hiding |
| 3 | 6 or more | over 25 mL or ongoing | white or gray gums, collapse |
Grade 0 gets 48 hours of photographs and stool checks. Grade 1 books within 72 hours. Grade 2 goes today. Grade 3 goes now, and a cat with white gums should be carried, not walked.
False alarms worth ruling out
Red food dye, beet-based treats, tomato sauce, and some dental chews produce red vomit with no blood at all; wipe a sample on a white paper towel, and a true blood stain turns brown as it dries while dye stays pink. A cat that chewed a houseplant may vomit red parts of the plant. A hairball with a few red threads is usually throat irritation from 2 or 3 retches, not a stomach bleed. If a toxin is possible, check the toxic plant and product checker before you decide the blood is the main problem, because some poisons cause both vomiting and bleeding.
When to see a vet
Six criteria, any 1 of them means today: more than 2 blood vomits in 24 hours; estimated blood over 10 mL; coffee-ground material with pale gums; black tarry stool; blood plus a cat that has refused food for 24 hours or cannot stand; and any suspicion of a foreign body, rat bait, or human medication. Emergency, meaning now: white or gray gums, a heart rate over 240 beats a minute, collapse, or vomiting blood after a known toxin exposure. Two related pages help place the symptom: white foam vomit for the empty-stomach pattern, and vomiting triage for the counts that decide a visit.
Before you drive
- Photograph each vomit with a coin for scale and note the time.
- Bag a sample in a sealed container; 10 mL in a bag answers more than 10 minutes of description.
- Check the gums by pressing for 2 seconds; color should return in under 2 seconds.
- Count the resting breathing rate for 30 seconds and double it; over 40 means hurry.
- Skip food for 4 to 6 hours only if your vet says so; do not give human antacids or painkillers.
Frequently asked
Is one vomit with a little blood serious?
Usually not, if it is 1 episode in 24 hours, the blood is a few streaks in foam, and the cat eats and drinks afterwards. Photograph it, check the litter box for black tarry stool, and watch for 48 hours. Two episodes in 24 hours books a visit within 72 hours, and more than 2 means today.
How much blood is too much for a cat?
Estimate in teaspoons: 5 mL per teaspoon, and a 2 cm pool on a hard floor is about 10 mL. Over 10 mL in 24 hours, or any bleeding that keeps returning, needs a same-day visit. A 4 kg cat holds roughly 260 mL of blood, so 25 mL is about 10% and is where the gums start going pale.
What does coffee-ground vomit mean?
It means blood sat in the stomach for 1 to 3 hours and was partly digested by acid, so the bleed is slower and older than bright red streaks. It can also come from swallowed blood after a nosebleed. Coffee-ground material plus pale gums is 1 of the 6 criteria that send a cat to the vet the same day.