Yes, my dog eats (and loves) lettuce. She holds it between her paws and pulls it apart to chew bit by bit, just as she would a treat. Since I had never seen a dog do that before I wondered if it’s ok to give her lettuce…or cucumbers, tomatoes, etc. I never thought to feed her a whole salad, but didn’t want to be poisoning her with the bits I did give. After all, I remembered we used to feed grapes to our old dog Pebbles (the people who had her before us named her). I now know that grapes are poisonous to many dogs. Luckily Pebbles was ok and lived for nearly 16 years, but better safe than sorry!
I found this site for what not to feed your dog: http://pets.webmd.com/dogs/slideshow-foods-your-dog-should-never-eat
And, if you have a cat, here’s one for your cat: http://pets.webmd.com/cats/slideshow-foods-your-cat-should-never-eat