CBSE Class 9 Answered

In vomiting, there is forceful expulsion of the contents of one's stomach through the mouth. During vomiting, there occurs a lowering of intrathoracic pressure coupled with an increase in abdominal pressure as the abdominal muscles contract. All this propels stomach contents into the oesophagus. Usually the feeling of nausea preceeds vomiting.

Vomiting may be due to many causes, ranging from gastritis, food poisoning, food allergies, appendicitis, hepatitis, motion sickness, concussion, cerebral hemorrhage, metabolic disturbances, pregnancy, reactions to drugs,eating disorders, violent emotions, disagreeable sights, brain tumors, etc.