Coffee ground emesis is the medical term for vomit containing partially digested blood, signaling bleeding in the upper gastrointestinal tract (esophagus, stomach, or duodenum). This appearance means the blood has been exposed to strong stomach acids before being expelled. Because this condition indicates a potentially serious internal hemorrhage, it is a medical emergency requiring immediate professional evaluation and care.
What Coffee Ground Emesis Looks Like
The name “coffee ground emesis” is used because the expelled material has a distinct dark brown or black, granular appearance, much like used coffee grounds. This is due to the clotted and partially broken down blood within the vomit. The texture is typically gritty, caused by the altered blood components.
This appearance is fundamentally different from vomiting bright red blood, which is called hematemesis. Bright red blood suggests active, fresh bleeding that has not remained in the stomach long enough to be altered by digestive acids. In contrast, the coffee ground presentation indicates the blood has been present in the stomach for a period of time, perhaps 30 minutes to several hours, allowing the stomach acid to begin digesting it. The presence of this symptom should prompt an immediate trip to the emergency room.
How Stomach Acid Creates the Appearance
The characteristic dark color and granular texture result from a specific chemical process involving the stomach’s powerful acid. When blood enters the stomach, the iron within the hemoglobin molecules is exposed to hydrochloric acid (HCl). The strong stomach acid oxidizes the iron component, converting the bright red hemoglobin into a dark brown or black compound called acid hematin or methemoglobin. This process effectively “digests” the blood, creating the grainy particles that resemble coffee grounds.
Medical Conditions That Cause This Symptom
The presence of coffee ground emesis indicates a source of bleeding within the upper gastrointestinal tract. A common cause is peptic ulcers, which are open sores on the lining of the stomach or duodenum. These ulcers can erode into a blood vessel, causing a hemorrhage that mixes with stomach acid. Peptic ulcers are often linked to chronic Helicobacter pylori infection or the regular use of nonsteroidal anti-inflammatory drugs (NSAIDs).
Severe gastritis, which is inflammation and erosion of the stomach lining, is another frequent cause. This irritation can lead to slow, persistent bleeding resulting in the coffee ground appearance. Similarly, esophagitis, inflammation of the esophagus lining, can cause erosions that bleed. Both conditions can be exacerbated by excessive alcohol consumption or long-term acid reflux.
In individuals with advanced liver disease, such as cirrhosis, pressure can build up in the veins leading to the liver. These swollen, fragile veins, called esophageal or gastric varices, can rupture suddenly, leading to significant bleeding. While variceal bleeding can sometimes present as bright red blood, partially digested blood may also appear as coffee grounds.
A Mallory-Weiss tear is a less common but significant cause, involving a tear in the mucous membrane lining of the lower esophagus. These tears are typically caused by forceful or prolonged retching and vomiting, which increases abdominal pressure. Determining the exact source of bleeding requires medical evaluation, often involving an endoscopy to visualize the upper digestive tract.