Vomiting may lead to serious fluid, electrolyte, and acid-base disturbances and can occur for a variety of reasons. By carefully observing the characteristics of the vomitus and, as needed, questioning the patient, you may gain clues as to the underlying disorder. Here's what the vomitus may indicate.
Bile stained (greenish)
Obstruction below the pylorus, as from a duodenal lesion
Bloody
Upper GI bleeding, as from gastritis or peptic ulcer (if bright red) or from gastric or esophageal varices (if dark red)
Brown with a fecal odor
Intestinal obstruction or infarction
Burning, bitter tasting
Excessive hydrochloric acid in gastric contents
Coffee-ground consistency
Digested blood from slowly bleeding gastric or duodenal lesions
Undigested food
Gastric outlet obstruction, as from gastric tumor or ulcer