Your history is suggestive of bleeding in the upper gastro-intestinal tract. The cause of this can be many, such as gastritis
, gastric ulcer, duodenal ulcer
, mallory-weiss tears, oesophageal varices. To know the exact cause, an upper GI Endoscopy
is required. As this is a single episode of vomiting of less quantity, a period of observation with abstinence from alcohol and a course of Proton Pump
Inhibitors is advisable. If you get repeated altered vomiting, i suggest you to get an endoscopy done.