Short answer
There is no safe amount of chives for a cat. As a member of the allium family, even a small lick or a tiny piece can start damaging red blood cells, leading to anaemia. The toxic effects are cumulative, so repeated small exposures over time are also dangerous. Symptoms like weakness, pale gums, or orange-tinged urine may take a day or two to appear. If you suspect any ingestion, contact your veterinarian immediately — do not wait to see how much they ate or if signs show up.
Chives — Food safety facts
Do not feed · Cats · full breakdown on the linked food page
An allium, like onion and garlic. Damages red blood cells and causes anaemia.
The full verdict, portion guidance and serving notes are collected on the Chives food facts page.