Your cat is back in the litter box, straining, and nothing is coming out. Or she skipped dinner and is tucked behind the couch where she never sits. It's 11 PM, the regular clinic closed hours ago, and the emergency hospital is a drive and a few hundred dollars before anyone touches her. You're trying to decide whether this waits until morning or whether every minute counts.
Cats make this harder than dogs. A dog in trouble tends to show it. A cat hides illness until late, because the instinct that kept a small predator alive in the wild is to look fine right up until it can't. So the signs that matter in a cat are often quieter, and a few of them are specific to cats in ways most owners never get told. What helps is a framework. Not a symptom list. A way to sort what you're seeing into go now, call today, or watch and call in the morning.
The go-now list
These signs mean drive to the emergency hospital. Don't wait to see if it settles. The Merck Veterinary Manual, the reference textbook most clinicians keep on the shelf, treats each of these as a true emergency.
Straining in the litter box with little or no urine. This is the feline emergency owners miss most. Repeated trips, crying in the box, only a few drops, licking at the genitals. In a male cat especially, this can mean the urethra is blocked, and a cat that can't pass urine is in danger fast. Cornell's Feline Health Center is direct that a blocked cat is life-threatening. The first blocked tom I helped restrain in Albany came in on a Saturday looking like he had a stomachache. He didn't. He had hours.
Open-mouth breathing or panting at rest. Cats breathe through their noses. A cat breathing with its mouth open, or with the belly pumping hard, when it hasn't just been running or sitting somewhere hot, is a cat in respiratory trouble. Blue, gray, or white gums alongside it raise the urgency further.
Sudden weakness or paralysis in the back legs. Crying, dragging the hind end, back feet that feel cold. This can be a blood clot lodged where the main artery splits toward the legs, and Cornell ties this saddle thrombus to heart disease that often gave no warning before this moment. It is painful and it is urgent.
Known toxin. Lilies are the one cat owners underestimate. True lilies cause acute kidney failure in cats, and the ASPCA Animal Poison Control Center counts every part as toxic, down to the pollen and the vase water. Acetaminophen, the drug in Tylenol, is another: the Pet Poison Helpline warns a single tablet can kill a cat. Antifreeze, rodent poison, and any human medication belong here too. Call the ASPCA at 888-426-4435 or the Pet Poison Helpline at 855-764-7661 while you get in the car, and don't induce vomiting unless a toxicologist tells you to.
Collapse or unresponsiveness. A cat that won't wake, won't lift its head, or doesn't register that you're there. Not groggy. Not sleeping.
Repeated vomiting with no water staying down, or a tense, distended, painful belly. One hairball is one thing. A cat retching over and over, or one whose abdomen is hard and sore, is another.
Trauma, a bad fall, or uncontrolled bleeding. Cats fall from open windows and balconies more than people expect. Even a cat that gets up and walks after a fall or a car can have injuries that don't show for hours. Bleeding that soaks through and won't slow with pressure goes now.
A seizure that lasts more than five minutes, or a second one within a day.
The call-today list
These are real and worth a same-day call to the clinic. They aren't usually midnight runs if your cat is otherwise alert and responsive. The clinic will tell you whether to come in. That's what the phone call is for.
Not eating for more than a day. A cat that turns down food needs attention sooner than a dog would, because cats who stop eating can slide into a dangerous liver condition. Two to three days off food earns a same-day visit. The walk-through of what it means when a cat stops eating covers where that line sits.
A sudden jump in drinking and peeing. A cat emptying the water bowl and flooding the box, especially an older one, points toward kidney disease, diabetes, or thyroid trouble. Not an emergency tonight, but a call this week.
A squinting or suddenly cloudy eye. Eyes move fast. A painful, weepy, or hazy eye is a same-day problem before it becomes a worse one.
Limping that holds steady. A cat putting some weight on the leg, not crying, still eating and alert, can wait for a daytime appointment. A leg that's dangling, hot, or obviously deformed moves up to the go-now column.
The watch-and-call-in-the-morning list
A single hairball with normal energy after. One soft stool in a cat who's otherwise fine. A sneeze or some eye discharge in a cat still eating, which is usually a mild upper-respiratory bug. A small scab or scrape that isn't bleeding. A new lump you hadn't noticed, which doesn't become an emergency overnight. Note it, take a photo, and bring it up when the clinic opens.
The gray zone: how to read what you see
Most nights the question isn't whether your cat needs a vet. It's whether she needs one right now. Three checks tell you more than the symptom itself.
Gum color. Lift the lip and look at the gums. Healthy gums are pink, like the inside of your wrist. Press a fingertip to the gum for two seconds and let go. The color should come back within two seconds. Pale, white, gray, blue, or bright-red gums are all reasons to drive. This one check reads your cat's circulation better than anything else you can do at home.
Breathing at rest. Watch the chest from a few feet away and count the rises for 30 seconds, then double it. A calm cat that stays above 30 breaths a minute, or one breathing with its mouth open or its belly heaving, has a breathing problem until proven otherwise. Effort matters as much as speed.
Engagement, not just hiding. A cat hiding is not the same as a cat shutting down. A cat tucked away who still lifts her head, tracks you, and responds to her name is different from one whose eyes are open but who doesn't seem to know you're in the room. The second is a reason to go. And trajectory counts: a sign that's holding steady over an hour is different from one getting worse every 20 minutes.
What to have ready before you go
The ER vet is meeting your cat cold. Everything you bring shortens the time between the door and treatment. Write the timeline: when it started, what changed, what you tried. Take a short video, especially of breathing or of the litter-box straining, because 15 seconds of footage tells the vet more than a sentence can. Know what medications she's on with doses, and when she last ate, drank, and used the box. If a toxin is involved, bring the packaging or the plant. The emergency vet guide has a printable checklist, and the triage guide walks through reading what a cat's body is telling you.
About cost
Emergency care is expensive, and that's a fact, not a judgment. An exam runs $150 to $300 before anything else, and a blocked cat that needs a catheter and a night of monitoring can reach $1,500 to $3,000. Cost shapes the decision whether anyone admits it or not. What I can tell you is this: if the sign is on the go-now list, go, and sort the payment from the waiting room. Most emergency hospitals offer plans or take CareCredit. For everything in the gray zone, a phone call costs nothing. Call the ER front desk and describe what you're seeing. They answer the phone for exactly this moment.
Three questions, in order
Standing in the kitchen at 11 PM, run these. They take a minute.
1. Is this on the go-now list? Straining with no urine, open-mouth breathing, back legs gone, a known toxin, collapse, repeated vomiting, trauma, or a long or repeated seizure. If yes, go. Stop here.
2. What do the gums look like? Pink and refilling in under two seconds is reassuring. Anything else, go.
3. Is it getting worse? Check twice over 30 minutes. Stable or improving can usually wait for a morning call. Getting worse means go. When you're still not sure, call the ER, the way the AVMA's emergency care guidance lays out from the veterinary side. The front desk answers so you don't have to decide alone.
A clear timeline, a current medication list, and a 15-second video are worth more to the ER vet than an hour of worry. Veta's pet health passport keeps your cat's history, medications, and symptom notes in one place, so when the vet asks what she's on and when her last bloodwork was, the answer is already there. The page on observing your pet covers how to learn your cat's normal so you can spot the moment it changes. The same triage logic applies to dogs, and the companion guide on when to take a dog to the emergency vet runs the canine version of these same checks.
Questions cat owners ask at the ER door
My cat keeps going to the litter box but nothing comes out. Is that an emergency?
Yes, treat it as one, especially in a male cat. Repeated trips to the box, straining with little or no urine, crying in the box, or licking at the genitals can mean the urethra is blocked. A blocked cat cannot pass urine, and Cornell's Feline Health Center is direct that this is a life-threatening emergency because toxins back up fast once the bladder can't empty. The window is short, often under 24 to 48 hours before it turns critical. Don't wait to see if the next trip is different. Call the emergency hospital and head in.
My cat is breathing with its mouth open. What does that mean?
A cat breathing through its mouth, panting, or heaving with its belly is a go-now sign unless the cat just got done with something stressful or hot and settles within a few minutes. Cats breathe through their noses. Open-mouth breathing at rest often points to fluid around or in the lungs, sometimes from heart disease. Watch the cat from across the room and count the breaths over 30 seconds, then double it. A resting or sleeping rate that stays above 30 breaths a minute is worth a call even if nothing else looks wrong.
How much does an emergency vet visit cost for a cat?
The exam alone usually runs $150 to $300 before any diagnostics, and after-hours surcharges add $50 to $150 on top. A blocked cat that needs a urinary catheter and a night of monitoring can reach $1,500 to $3,000. The cost is real and it matters. The signs on the go-now list don't negotiate with it. If your cat is in that category, go, and work out payment with the clinic after. Most emergency hospitals offer plans or take CareCredit.
My cat ate part of a lily. Do I need to go in?
Go now, and bring the plant. True lilies, the kind in Easter and bouquet arrangements, cause acute kidney failure in cats, and the ASPCA Animal Poison Control Center counts every part as dangerous, including the pollen and the water in the vase. A cat that brushed the pollen off its fur while grooming has had a dose. Call the ASPCA at 888-426-4435 or the Pet Poison Helpline at 855-764-7661 on the way. Treatment started early, before the kidney damage sets in, is what changes the outcome.
Can I give my cat a little Tylenol or ibuprofen for pain?
No. Never give a cat human pain medication. Acetaminophen, the drug in Tylenol, is one of the most dangerous things in the house for a cat, because cats can't process it the way people do, and the Pet Poison Helpline notes that even a single regular tablet can be fatal. Ibuprofen and aspirin are also toxic. If your cat got into any human medication, call a poison line and head to the clinic. The dose your vet sets for feline pain is the only safe one.
My cat suddenly can't use its back legs and is crying. What is happening?
Drive to the emergency hospital. Sudden weakness or paralysis in the back legs, often with crying, dragging, and back feet that feel cold, can be a blood clot lodged where the aorta splits to the hind legs. Cornell ties this saddle thrombus to underlying heart disease in cats, sometimes as the first sign anything was wrong. It is painful and time-sensitive. This is not a wait-and-see symptom.
My cat hasn't eaten in a day. Is that worth an emergency visit?
A cat that turns down food for more than a day needs a call to the vet, and a cat that hasn't eaten in two to three days needs to be seen, because cats who stop eating can develop a dangerous liver condition called hepatic lipidosis. It isn't usually a midnight ER run on its own unless the cat is also vomiting, hiding, or clearly painful. The walk-through of what it means when a cat stops eating covers where the line is.
My cat is hiding more than usual. Should I be worried?
Cats hide pain better than almost any animal, so a cat tucked in a closet who still comes out, eats, and uses the box is showing a soft signal, not an emergency. The picture changes when the hiding comes with a symptom: not eating, straining in the box, fast or open-mouth breathing, or a cat who won't come out at all and doesn't respond to you. A cat that's hiding because it can barely move is a different animal than one who just wants to be left alone. When the hiding pairs with any go-now sign, treat the go-now sign as the answer.
Join the Veta waitlist
Keep your cat's medications, history, and symptom notes in one place, so the answer is ready before the ER vet asks. When Veta opens for iOS, we'll tell you first. No spam, no roadmap emails. One note when the app is ready to download.
Rachel Howland, CVT (ret.), spent a decade in clinic: seven years in a mixed practice in upstate New York, then three on the internal-medicine floor at Angell Animal Medical Center in Boston. She left practice in 2017 and has written about small-animal health since. She lives in Somerville with Juno, an 11-year-old hound mix managing chronic kidney disease, and Bishop, a Siamese cat. She does not diagnose or prescribe; she explains what your vet's records are telling you and what questions are fair to ask.