Cat is throwing up

My cat seems to be throwing up saliva. My vet says he's healthy. Could he be doing this as a sign of stress? Some underlying health condition? As a defense mechanism against some mice? (We just started to see droppings so Idk how long we've had a mice problem)

Can you provide more information? What color is the vomit? Clear liquid? Brownish? Foam?

When does your cat tend to throw up? Morning? Night? Near mealtimes? etc?

Vomiting can definitely be a sign of stress, but without further detail it's difficult to even begin to theorize what might be happening.

At first lots of hairballs, then just saliva. He also had diarrhea which seemed brown liquid but now is mucous like clumps. He saw the vet again today for an xray. She suspects IBD or cancer based on the intestines appearing white on the xray. We are trying steroids and antibiotics. feeling defeated

White on x-rays is usually calcium... or poop in colon..

Is your cat constipated?

Is your Vet sending the x-ray to a Radiologist, a doctor who reads x-rays, for interpretation?

That is what I would do...

Can you take you cat to a E-Vet? expensive, I know, but it may save her life..

I don't think he's constipated, he had diarrhea and normal stools up until now. She said his xray showed no poop at all. I can't afford another vet or the ultrasound.