What one vomiting episode tells you about a 4 kg cat
That single vomit suggests her stomach rejected the unfamiliar fiber, not that she's poisoned. Cats often purge new greens simply because they're not meat—it's a texture protest. At her size, one leaf is a modest amount, so the main risk now is dehydration if she keeps vomiting.
Check the vomit for undigested leaf pieces; if you see them, her stomach barely tried to digest it. Clear or foamy vomit means her system flushed itself thoroughly. Neither case requires panic unless it happens again within hours.
The 24-hour watch checklist
First, offer water but no food for two hours to let her stomach settle. When you reintroduce meals, start with half her usual portion. Her next few bathroom trips might be looser as the fiber passes—only worry if she strains painfully or has bloody diarrhea.
Lethargy is a bigger red flag than more vomiting; cats hide illness well, so if she sleeps heavily or ignores toys she normally loves, call the vet. Most likely though, she'll be begging for food by tomorrow.
What the vet would examine if you go in
They'll press her belly to check for tender spots unrelated to the endive, since cats sometimes vomit for hidden reasons. Expect temperature checks and possibly subcutaneous fluids if she seems dehydrated from vomiting. The vet might also suggest bloodwork if her gums look pale or her reactions seem slow, but that's precautionary.
Bring a sample of the vomit if possible—odd colors or foreign objects in it change the diagnosis. For plain plant matter though, they'll likely send you home with instructions to monitor rather than treatments.
Why future green treats might need prep
If she enjoyed the endive before vomiting, try steaming it next time to soften the fiber. Some cats handle cooked greens better. You can also mince it finely and mix into her wet food as a test—smaller pieces are less likely to trigger rejection.
Watch for grass-chewing urges too; cats that crave greens might need safer alternatives like cat grass. One vomiting episode doesn't mean she can't have veggies—it just means her stomach needs slower introductions.
The full verdict, portion guidance and serving notes are collected on the Endive food facts page.