Dates — Food safety facts
Feed with care · Cats · full breakdown on the linked food page
High in sugar and sticky — remove the pit first. Very small pieces only.
Short answer
It's okay with caution. Dates are not toxic, but they are high in sugar and very sticky, which can be a choking hazard or cause an upset stomach. Always remove the pit first and only offer a very tiny piece as an occasional treat. Watch for any signs of vomiting or diarrhea, and if those appear, contact your own vet.