Nausea and Vomiting

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Overview & Considerations

Your body has a few main ways to respond to an ever-changing, wide variety of invaders and irritants. Sneezing ejects the intruders from the nose, coughing from the lungs and throat, diarrhea from the intestines, and vomiting from the stomach.

Vomiting is a forceful action accomplished by a fierce, downward contraction of the diaphragm. At the same time, the abdominal muscles tighten suddenly against a relaxed upper stomach with an open sphincter. The contents of the stomach are propelled up and out.

You may have more saliva just before vomiting. Retching signals the beginning of vomiting.

Vomiting is a complex, coordinated reflex orchestrated by the vomiting center of the brain. It responds to signals coming from:

• The gastrointestinal tract, including the mouth, stomach, and intestines
• The bloodstream and medicines or infections in the blood
• The balancing systems in the ear (think motion sickness)
• The brain itself, including unsettling sights, smells, or even thoughts

An amazing variety of stimuli can trigger vomiting, from migraines to kidney stones. Sometimes, just seeing someone else vomit will start you vomiting, in your body's effort to protect you from possible exposure to the same danger.

Vomiting is extremely common. Almost all children will vomit several times during their childhood. In most cases, it is due to a viral gastrointestinal infection.

Spitting up, the gentle sloshing of stomach contents up and out of the mouth, sometimes with a burp, is an entirely different process. Some spitting up is normal for babies, and usually gets gradually better over time. Worsening spit up might be GE reflux disease, and should be discussed with your doctor.

Most of the time, nausea and vomiting do not require urgent medical attention. However, if the symptoms continue for days, if they are severe, or if you cannot keep down any food or fluids, they may be signs of a more serious condition.

Dehydration is the primary concern with most vomiting. How fast you become dehydrated depends on your size, frequency of vomiting, and whether you also have diarrhea.