Our 3 year old cat has started to vomit increasingly more often to around 4 times per week.

[WesGerrard]

We have taken her to the vet twice.
The first vet we saw in February this year recommended ‘no treats’ which we adhered to however the vomiting remained consistent.
We have given both vets a comprehensive history as follows:
house move and new baby within the last 12 months
She has always been a sickly cat but the vomiting has gotten worse since earlier this year
We don’t have anything in the house that could make her sick (we know which plants and flowers are toxic and only ever have roses in the house) even the floor cleaner we use is pet safe
She has a felliway plug in to help with the environmental changes
wee’ing and pooping is fine. She is a house cat and uses a tray
She is regularly wormed and flea’d
She eats James Wellbeloved dry and Sheba wet food
She has always drunk plenty of water
Both vets have conducted a thorough palpation.
The second vet we saw last week and the week before took 2 lots of blood tests. The results came back as normal (organs are fine and no pancreatitis her Vit B12 is within normal levels). This vet doesn’t think she has a blockage or anything too serious but has suggested that we put her on a hydrolysed diet for 6 weeks to see if there is any improvement. He advised if there was no improvement we could scan her to look for any abnormal masses and test her stool. He does not think that these are urgent as he suspects a dietary intolerance.
Has anyone had any success with a hydrolysed diet? Has anyone got any other suggestions?
As an interim solution we are currently trying grain free food and biscuits to see if it could be an intolerance to wheat or other grain.
Many thanks

[susand]

My cat is on Purina hypoallergenic food. The vet reckons this brand is the only really palatable hydrolysed food on the market and most cats won’t eat the other brands out there. I do think Harvey is better on it. He has skin issues rather than vomiting but he seems less itchy since I switched to it. Unfortunately it only comes as a dry food. I prefer to feed my cats a wet diet but since the Purina HA seems to be helping him he is on that now although it hasn’t completely cured the problem and he needs to take medication as well. Having said that, that is likely because he does get hold of food elsewhere, through scavenging, a bit of hunting and possibly scrounging from neighbours as well. Ideally he should be an indoor cat so I could have complete control over his diet but he loves going out too much for me to keep him in.

[Mollycat]

Did the vet offer or give any anti-emetic, or anti-nausea medication? I would have thought that was first before jumping to the conclusion that it must be a dietary intolerance, especially if it's the usual food and that hasn't been changed soon before the vomiting started.

Is it proper vomiting of food, is it happening straight after eating? Or frothy, or yellowish bile?

If she is an indoor cat, do you grow cat grass for her, or give her grass tablets? If you grow a pot of grass you can snip short bits for her to eat and that won't make her sick like long pieces can. Have you tried a drop of krill or salmon oil in her food? You could also try, with the vet's guidance on brand and dosage as getting it wrong can be dangerous, an H2 blocker antihistamine?

How often does she deliver hairballs?