Why is my dogs poop green?

Are you missing Gumby? Seriously, when my granddaughter did that I worried, I think Green is one of the safe colors. Vegetables, Ice cream, Don't know about a dog.
Any change in diet?

Then there is red from red beets. You poop what you eat,

Has it been eatting grass?

Good question. My dog's poop is green too! I think it comes from something in his puppy chow. Every now and then he manages to swallow a leaf before I can get it out of his mouth, but I don't think he's eating enough of them to have any effect on his poop color. He doesn't eat grass because we live in a city and I haven't let him play in the public grassy areas because he still has to finish his vaccines. Let's see if we can get a poop expert in here...