The Facts

Vomiting is the act of forcefully expelling the stomach's contents out through the mouth. It's usually an involuntary action brought on by nausea, but can be deliberately provoked. Almost everyone has had this unpleasant experience at least once (if not many times) in their life.

Nausea refers to the unpleasant "queasy" feeling that you get when you're about to vomit, one that's accompanied by uncontrollable contractions of the stomach that begin before and continue during vomiting.

Nausea and vomiting aren't normally medical conditions themselves, but are commonly symptoms of a disorder or illness.

Causes

Vomiting has many and varied causes. It can be triggered by ingesting a toxin or poison (e.g., alcohol, a prescription or recreational drug, or contaminated food), by an inflammation of the stomach lining, or by a bowel obstruction. It may also occur in diseases that delay the emptying of the stomach, such as diabetes.

Injuries to the head, such as concussions, often lead to vomiting. Psychological factors may provoke vomiting in situations that are frightening or in some way horrifying or repulsive. People with motion sickness or other conditions of the vestibular (balance) system experience nausea and vomiting as a result of certain types of movement (e.g., travelling in a car or airplane). Migraine headaches may also cause nausea and vomiting.

Vomiting on purpose may play an important role in eating disorders such as anorexia and bulimia. When this is the case, it's hard to detect, even after weeks or months of constant vomiting. Although people who vomit like this may do so without losing weight or becoming dehydrated, induced vomiting can lead to malnutrition and metabolic abnormalities.

Nausea during pregnancy is common, especially during the first three months. For pregnant women and some other people, certain smells and tastes can cause nausea.

Medications and medical therapies can also produce nausea as a side effect. For example, chemotherapy treatment for cancer often causes nausea and vomiting. If you feel nauseous because of medication you're taking, you should decide with your doctor whether to put up with it (the nausea may be temporary), or to stop taking the medication. You may also be prescribed an anti-nausea medication to take with the medication causing the nausea.

If you vomit or feel the urge to vomit for a prolonged period of time, or if you feel sharp or severe stomach pain, you should seek medical attention. If you vomit anything other than the contents of your stomach (fluids and partially digested food), or produce vomit that contains blood, substances that look like coffee grounds, or something you think is odd or strange, see a doctor.

Making the Diagnosis

A physical examination, your health history, laboratory tests, and other tests are all used by your doctor to find the cause for your nausea and vomiting.

In most cases, the cause of nausea and vomiting is easily identified, as it may occur in a known pregnancy or shortly after ingesting a drug or toxin.

Vomiting can be an indication of serious health problems such as gall bladder inflammation, intestinal obstruction, peptic ulcer disease, acute hepatitis, complications from diabetes, acute gastroenteritis (stomach flu), meningitis, and cancer.

Bacterial and viral infections, which include "stomach flu," are common causes of nausea and vomiting. These conditions, however, are often accompanied by other familiar symptoms such as aches and fever.

Pregnancy should be considered a potential cause for any female of childbearing age.

Treatment and Prevention

In most simple cases of vomiting, it will stop on its own once the contents of the stomach have been expelled. This only takes a few minutes, but you can still feel nausea and keep retching after your stomach has emptied.

For healthy adults and older children simple cases of vomiting do not usually require further medical attention. Drinking clear fluids can help prevent dehydration. When older adults and young children have prolonged vomiting (i.e., more than one day) or have other symptoms such as stomach pain, swollen stomach, headache, confusion, or weakness they should be seen by a doctor.

For people who are nauseated by strong smells and tastes, avoiding these triggers can help, as can eating small amounts of bland food, such as crackers, throughout the day.

When vomiting is persistent, anti-nausea medications can be prescribed, and tests can be conducted to find an underlying cause or more extensive health problem. In severe cases, the medications may need to be given as an intravenous injection (into the vein) if a person is actively vomiting. Taking anti-nausea medications for a long time isn't recommended, and they shouldn't be taken during any stage of pregnancy without consulting a physician first. Antihistamines, such as dimenhydrinate*, may be used when the nausea and vomiting is caused by motion sickness.

Pregnant women who experience nausea and vomiting should talk to their doctor about medications that are thought to be safe for both them and their baby.