4 Answers

One possible cause is that you ate a lot of food coloring.  If you rule out this, you might have problems with your intestine.  See your doctor.

very bad  goto dr. asap

God ran out of brown crayon. :o

Healthy people can have green poop if they eat a diet rich in leafy green vegetables, or if they consume large quantities of food coloring (in ice cream, cake frosting etc.).
Green poop can also be caused by excess iron in the diet, from dietary supplements, for example. If the body does not absorb all the iron consumed, the iron may stain the poop green, the color of iron (II) salts. Ordinarily, the green color may be masked by the normal brown poop color, but if digestion is thrown off by illness so that bilirubin is less concentrated in the intestine, the green color may become apparent. This can happen when a person is afflicted with diarrhea.
Green poop in sick babies may come from iron in baby formula not being properly absorbed, or by green pigments in bile salts (again, green from iron).