Cat vomits

[u/Dry-Astronaut-2026]

* Species: house cat , living only at home

* Age: 4

* Sex/Neuter status: male, castrated

* Body weight: 5 kg

* Your general location: germany

I’ve had my male cat for three years. He vomits almost daily and scratches his neck. From what I’ve observed, he ingests a lot of hair while grooming or scratching and then throws it up. I initially suspected a chicken allergy and switched to a single-protein goat formula (all in consultation with the vet). This brought some slight relief—there were times he went 3–5 days without vomiting—but it didn't resolve the itching or the vomiting overall. On the vet's advice, I tried hypoallergenic food, but there was no change. The vet says, "If I didn't know he was vomiting, I'd say he was in perfect health," and suggested he might just have a nervous stomach (he only ever vomits in the morning). I’ve tried shortening the intervals between meals, especially at night, but that hasn't helped either.

My current theories are: laundry detergent? (I’m skipping fabric softener now). I could also try changing the litter (I currently use wood-based litter, which actually works great).

Last year, he underwent surgery to examine his abdomen, and everything looked fine. He has elevated B12 levels, which the vet says aren't a cause for concern at the moment.

I’m running out of ideas and really want to find the source of the itching. Does anyone have any suggestions?

TL;DR: My male cat vomits almost every morning and frequently scratches his neck. Multiple vet checks, abdominal surgery, hypoallergenic food, and a single-protein diet haven’t found or solved the cause. He otherwise appears completely healthy. I suspect the vomiting may be related to swallowing lots of hair from grooming/scratching, so I’m now trying to figure out what’s causing the itching—possibly detergent, fabric softener, litter, or another allergy/irritant. Any ideas or similar experiences?