Nausea and vomiting

Nausea is an uneasiness of the stomach that often accompanies the urge to vomit, but doesn't always lead to vomiting. Vomiting is the forcible voluntary or involuntary emptying ("throwing up") of stomach contents through the mouth. Some triggers that may result in vomiting can come from the stomach and intestines (infection, injury and food irritation), the inner ear (dizziness and motion sickness) and the brain (head injury, brain infections, tumors and migraine headaches). Nausea and vomiting can occur in both adults and children of all ages. People undergoing cancer treatments, such as radiation therapy or chemotherapy, have an increased risk of nausea and vomiting. Pregnant women in their first trimester may also experience nausea and vomiting, commonly referred to as "morning sickness." It is estimated that 50 to 90 percent of pregnant women experience nausea, while 25 to 55 percent experience vomiting.

Nausea and vomiting are controlled by the same parts of the brain that control involuntary bodily functions. Vomiting is actually a reflex triggered by a signal from the brain. The causes of nausea and vomiting are quite similar. Many things can bring on nausea. Some common causes are seasickness and other motion sicknesses, early pregnancy, intense pain, exposure to chemical toxins, emotional stress (fear), gallbladder disease, food poisoning, indigestion, various viruses and certain smells or odors. The causes of vomiting differ according to age. For adults, vomiting is commonly a result of a viral infection and food poisoning, and occasionally a result of motion sickness and illnesses in which the person has a high fever. For children, it is common for vomiting to occur from a viral infection, food poisoning, motion sickness, overeating or feeding, coughing, and illnesses in which the child has a high fever. Although rare, blocked intestines can result in vomiting, most typically in early infancy.

More information on vomiting