Blood vs. not. A classic description of coffee ground vomiting in medicine is suggestive of bleeding in the upper GI tract, more frequently from an active stomach or duodenal ulcer, however, I do see a lot of people who claim to have had this time of vomiting when in reality no ulcer is found. Some foods may like jam may mislead one. I would still see a physician to rule out bleeding as it is of major concern.
GI bleed. Coffee ground vomiting may indicate a GI bleed, that is a bleed anywhere in the upper abdomen, such as the esophagus (food tube) or stomach. Coffee-ground vomiting needs investigation by a doctor.