Nausea is an uneasiness of the stomach that often comes before vomiting . Vomiting is the forcible voluntary or involuntary emptying ("throwing up") of stomach contents through the mouth .

What Causes Nausea or Vomiting?

Nausea and vomiting are not diseases, but they are symptoms of many conditions such as:

The causes of vomiting differ according to age. For children, it is common for vomiting to occur from a viral infection, food poisoning, milk allergy, motion sickness, overeating or feeding, coughing, or blocked intestines and illnesses in which the child has a high fever.

The timing of the nausea or vomiting can indicate the cause. When appearing shortly after a meal, nausea or vomiting may be caused by food poisoning, gastritis (inflammation of the stomach lining), an ulcer, or bulimia. Nausea or vomiting one to eight hours after a meal may also indicate food poisoning. However, certain food- borne bacteria, such as salmonella, can take longer to produce symptoms.