Food safety
Can dogs eat lettuce?
Yes — fine in small amounts
Harmless and mostly water. Not exciting, but fine.
How much
A little, chopped
Being honest about this
Dogs differ, and amount matters — a crumb of something rich is not the same as half a packet. Treats of any kind should stay under a tenth of what your dog eats in a day. If you're unsure, your vet would far rather take the call.