Hello, Colored vomiting in absence of any colored fluid or food is definitely indicative of gastric bleeding if coffee colored or red unless proved otherwise. Another reason can be intestinal obstruction causing digested food to be vomited but then there will be other signs and symptoms of obstruction like bloating, severe pain and so on. You are taking Doxycycline and took alcohol too can surely cause gastritis or gastric ulcer that caused bleeding too. Hence, I would advise you the following in such a situation: - Get an opinion at the ER for getting an Emergency Upper GI Endoscopy and other tests and get specific treatment - Get started on a PPI like Pantoprazole, antacid every three hours - Cold milk and such liquids only - Soft and bland diet only - No smoking or drinking Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. T Chandrakant