Black-green loose stools may be physiological factors or clinical symptoms of certain diseases, such as indigestion, intestinal flora imbalance, intestinal infections and so on. 1. Physiological factors: Normal people can have transient black-green loose stools after eating dark green vegetables or blood products, without special treatment. 2. Pathologic factors: (1) Dyspepsia: When dyspepsia occurs, the food residues in the intestinal system and the alkaline substances in the intestines have a short time to neutralize, and the feces are acidic, and the bilirubin in feces is oxidized to bilirubin in an acidic environment, so that the discharged feces will be blackish-green and unshapely. (2) Imbalance of intestinal flora: Imbalance of intestinal flora can cause Pseudomonas aeruginosa to multiply too much in the intestines and produce green fluorescent pigment, resulting in loose stools and stools turning green. (3) Intestinal infection: when there is an infection in the intestines, under the stimulation of bacteria or viruses, an intestinal inflammatory reaction can occur, and the mucus secreted in the intestines seeps out, which can be manifested as the phenomenon of black-green loose stools. There are many other reasons for the discharge of black-green loose stools, it is recommended that patients seek timely medical care, under the guidance of a professional physician to clarify the cause of the disease, and comply with the doctor’s instructions for treatment, to avoid delaying the condition.