Adults may eat too much green vegetables, but also may be caused by gastrointestinal disorders and other diseases. 1. Eating too much green vegetables: such as eating too much greens, leeks, spinach and other green vegetables, can be caused to solve the green stool. 2. Gastrointestinal dysfunction: a group of chronic or recurrent gastrointestinal syndromes without organic lesions upon examination. It can cause intestinal motility disorders, leading to indigestion of food, causing green stools. It is also usually accompanied by abdominal pain, diarrhea, constipation, a feeling of impurity in defecation, belching, loss of appetite and other symptoms. There are many other causes of green poop in adults, which should be taken seriously, and prompt medical attention should be given to identify the cause of the problem and further management or treatment as prescribed by the doctor.