Gastroesophageal reflux disease (GERD) with esophagitis or gastritis: This condition is the most common cause of coffee ground emesis due to the reflux of stomach acid into the esophagus, leading to inflammation and potential bleeding.

Peptic ulcer disease (PUD): Both gastric and duodenal ulcers can cause bleeding, leading to coffee ground emesis. The presence of Helicobacter pylori, NSAID use, or stress can contribute to the development of PUD.
Mallory-Weiss syndrome: This condition involves tears in the mucous membrane or lining of the lower end of the esophagus, where it connects to the stomach. These tears can bleed, resulting in coffee ground emesis, often after intense or prolonged vomiting, retching, or coughing.
Esophageal varices: While more commonly associated with hematemesis (vomiting blood), esophageal varices due to liver cirrhosis and portal hypertension can occasionally present with coffee ground emesis if the blood is partially digested.

Boerhaave's syndrome: A severe and life-threatening condition involving a full-thickness tear of the esophagus, which can present with vomiting, including coffee ground emesis, along with severe chest pain and difficulty swallowing. Prompt diagnosis and treatment are crucial.
Aortic dissection or rupture: Although rare, an aortic dissection or rupture can lead to bleeding into the mediastinum and potentially cause vomiting, including coffee ground emesis, due to pressure effects on the esophagus or stomach.
Ectopic pregnancy: In rare cases, an ectopic pregnancy can cause abdominal pain and bleeding that might lead to coffee ground emesis, especially if there is significant intra-abdominal bleeding affecting the gastrointestinal tract.

Dieulafoy's lesion: A rare cause of gastrointestinal bleeding, characterized by a small, superficial ulceration with an exposed, often large, caliber artery at its base. It can cause significant bleeding leading to coffee ground emesis.
Gastric cancer: While not typically the first presentation, advanced gastric cancer can cause bleeding, leading to coffee ground emesis. This diagnosis is more common in certain geographic areas and in individuals with specific risk factors.
Ingested foreign body: Sharp objects can cause esophageal or gastric perforation and bleeding, potentially resulting in coffee ground emesis. This is more common in children or individuals with certain psychiatric conditions.