Basil — Food safety facts
Safe to share · Cats · full breakdown on the linked food page
A few fresh basil leaves are safe for dogs and cats. Not toxic in normal amounts.
Short answer
Yes, a few fresh basil leaves are safe for cats. Basil is not toxic to cats in normal amounts. You can give a small piece as a treat, but keep it plain and free of oils or seasonings. Watch your cat for any signs of stomach upset such as vomiting or diarrhea, and contact your vet if anything seems off.