What Does Green Poop Mean?

Feces can changed color based on diet. Your dog may have eaten something green in color or a large amount of grass or plant material. Also stool coloration is affected by the type of bacteria present.
Also greenish color can be from increased gastrointestinal transit time; not enough time to reabsorb bile pigment.
Rodenticide toxicity in some cases can lead to greenish stool; I would expect other signs if this were the case.
Have a veterinarian examine a stool sample if this coloration continues, diarrhea develops or a toxicity may have occurred.

Depends on what he eat,as this sometimes happen to humans.

I don't know actually I wonder that sometimes to I think it might be like a diet it changes color cause your eating better I don't know actually really?????