Coffee ground vomiting

Overview
Coffee ground vomiting refers to a particular appearance of vomit. Blood contains iron within heme molecules in red blood cells. When this iron has been exposed to gastric acid for some time, it becomes oxidized. This reaction causes the vomitus to look like ground coffee. Coffee-ground vomitus is a classic sign of upper gastrointestinal bleeding. A peptic ulcer, for example, may bleed into the stomach and produce coffee-ground vomitus. When bright red blood is vomited, this is termed hematemesis.

Hematemesis, in contrast to coffee ground vomitus, suggests that upper gastrointestinal bleeding is more acute or more severe, or originates more proximal to the stomach: for example, in the esophagus due to a Mallory-Weiss tear.

Oxidized blood from an upper gastrointestinal bleeding can also be excreted in stool. It produces tarry, blackened stools known as melena.