Hi, Welcome to health care magic, Black or dark loose stools could be a worrisome symptom because it may be due to bleeding into the gastrointestinal tract, most often the esophagus, stomach or duodenum. Red blood cells from the blood are broken down by digestive enzymes and turn the stool black. These stools tend to be tarry and foul smelling. This can be a medical emergency,black tarry stools should not be ignored. In your case,alcohol intake should not be the cause for dark runny stool here. Certain foods and some other medications can also turn stool black, including iron, bismuth (Pepto Bismol, loperamide), beets, and licorice. So,there is need to evaluate it further by doing blood and stool examination. In case,your dark stool remains persistent (for more than week or if you develop clinical symptoms) then you can see gastroenterologist who will take complete medical history with thoroughly clinical examination and advice you to undergo upper GI endoscopy. Hope this will help you. Regards,