Nausea is an unpleasant feeling of needing to vomit. People also may feel dizziness, vague discomfort in the abdomen, and an unwillingness to eat. Vomiting is a forceful contraction of the stomach that propels its contents up the esophagus and out the mouth. See also Vomiting in Infants and Children. Vomiting empties the stomach and often makes people with nausea feel considerably better, at least temporarily.
Vomiting is quite uncomfortable and can be violent. Severe vomiting can project stomach contents many feet projectile vomiting. Vomiting is not the same as regurgitation , which is the spitting up of stomach contents without forceful abdominal contractions or nausea.
For instance, people with achalasia or Zenker diverticulum may regurgitate undigested food without nausea. Vomitusβthe material that is vomited upβusually reflects what was recently eaten. Sometimes it contains chunks of food. When blood is vomited, the vomitus is usually red hematemesis , but if the blood has been partly digested, the vomitus looks like coffee grounds.
When bile is present, the vomitus is bitter and yellow-green. People who are unconscious or only partly conscious can inhale their vomitus. The acid in the vomitus can severely irritate the lungs. Vomiting greatly increases pressure within the esophagus, and severe vomiting can tear the lining of the esophagus see Esophageal Laceration Mallory-Weiss Syndrome.
A small tear causes pain and sometimes bleeding, but a large tear can be fatal. Because people lose water and minerals electrolytes in vomitus, severe vomiting can cause dehydration and electrolyte abnormalities. Newborns and infants are particularly susceptible to these complications. Chronic vomiting can cause undernutrition , weight loss, and metabolic abnormalities. Nausea and vomiting result when the vomiting center in the brain is activated.
