The short answer
Usually no. Most vets ask owners to withhold food for a set period before a cat is neutered or spayed, often starting the evening before. The exact timing differs by clinic, and kittens, older cats, and cats with health conditions may have different instructions, so follow the written or spoken instructions your own vet gives you. If you are not sure, call the clinic and ask rather than guessing.
Why cats are fasted before surgery
Surgery requires general anesthesia, which can cause nausea and vomiting. If a cat vomits while she is under or waking up, stomach contents can get into the airway and cause serious problems (aspiration). An empty stomach lowers that risk. That is why clinics are firm about fasting even if your cat seems hungry and vocal.
What the fasting instructions usually look like
Clinics commonly say something like:
- Give a normal last meal in the evening.
- Offer nothing after a set time that night, including treats.
- Do not feed anything in the morning.
The set time varies. One clinic may say no food after 9 or 10 pm, while another may suggest a different window. Because there is no universal cutoff, use the one on your appointment paperwork.
Water
Policies differ here. Some clinics allow water overnight and ask you to pick up the bowl in the morning. Others say water is fine until the morning of surgery. Ask what your clinic prefers. If your cat is on any medication, ask whether to give it that morning.
What if my cat ate by accident
Tell the clinic as soon as you notice, ideally before you leave home. Do not hide it. Depending on how recently she ate, the vet may postpone the surgery to a later time or date. Being honest protects her, since the anesthetic plan relies on knowing her stomach is empty.
Special situations
- Kittens. Very young kittens may have different fasting guidance from adults because they can have trouble keeping their blood sugar up. Ask your vet for their specific instructions.
- Cats with health conditions. Diabetic cats or cats with other conditions may need adjusted food and medication instructions. Never change these on your own.
- Multi-cat homes. Separate the cat having surgery so she cannot snack from another bowl. Pick up shared food overnight.
- Outdoor cats. Keep her in the night before so she does not eat something outside and is easy to find in the morning.
Other things to do the night before
- Get her used to her carrier by leaving it out with a soft blanket or treats beforehand.
- Keep the litter box available overnight.
- Allow extra time in the morning in case she hides.
- Write down the number where the clinic can reach you all day.
- Check any paperwork the clinic sent, including consent forms and any pre-anesthetic blood work.
Surgery day: what to expect
At drop-off, staff may do an exam and review consent. Some clinics offer pre-surgery blood work to check the liver and kidneys and screen for other issues, which is more often suggested for older cats. The cat is anesthetized, the surgery is done, and she is monitored while she wakes up. Many clinics send cats home the same day, often later in the afternoon. Ask how long to expect her to be at the clinic. For the surgery itself, see our overview of what age a cat can be spayed, which explains what is involved.
If a female cat is in heat, let the clinic know ahead of time. See spaying a cat in heat for why that matters.
Feeding after surgery
Your vet will give feeding instructions. Many clinics suggest a small amount of water and a small meal once she is awake and alert, and then a return to normal feeding the next day. Anesthesia can make cats drowsy and less hungry for a day or so, which is common; our guide to caring for a cat after anesthesia explains what to expect. Do not force-feed.
Call your vet if she:
- Refuses food and water the following morning, or still won’t eat after about 24 hours
- Vomits repeatedly
- Has diarrhea that doesn’t clear up
- Is very lethargic or hard to wake
It is also common for a cat not to have a bowel movement for a day or two after surgery. If she strains without producing urine, or passes no urine, treat it as a same-day emergency and call your vet or an emergency clinic now, especially for a male cat. More on warning signs is in spaying cat complications and risks.
FAQ
How long will my cat be at the vet?
It varies. Many cats are dropped off in the morning and picked up later the same day, but your clinic will tell you its schedule.
Can I give my cat water before surgery?
Often yes until bedtime or the morning, but clinics differ. Ask yours.
Do kittens need to fast too?
Often there is a different, shorter fasting window for very young kittens. Follow your vet’s guidance.
My cat hasn’t peed since surgery. Is that normal?
Not usually for long. If she is straining or crying in the litter box without producing urine, or passes no urine, this is a same-day emergency, especially in male cats. Do not wait; call your vet or an emergency clinic now.