Projectile vomiting is a forceful type of vomiting where stomach contents are ejected with enough power to travel several feet through the air. Unlike regular vomiting, which typically builds with waves of nausea and retching, projectile vomiting often strikes suddenly and without warning. It can affect anyone, but it’s most commonly associated with infants who have a specific stomach condition, and in adults it often signals a blockage or pressure buildup that needs medical attention.
How It Differs From Normal Vomiting
Regular vomiting usually comes with clear warning signs: nausea, salivation, gagging, and a building sense that something is about to happen. The stomach contracts in coordination with the diaphragm and abdominal muscles, and the result, while unpleasant, tends to come out with moderate force.
Projectile vomiting skips most of those preliminary signals. It can happen abruptly, with little or no nausea beforehand, and the vomit travels with significantly more force. In infants, parents often describe it shooting across the room. This sudden, violent quality is what makes it diagnostically important: it suggests the body is dealing with something beyond a simple stomach bug.
It’s also worth distinguishing vomiting from spitting up, especially in babies. Spitting up is a gentle flow of milk or formula out of the mouth, usually with a burp. It happens in most infants during their first few months and doesn’t interfere with weight gain. Projectile vomiting is an entirely different event, forceful and repeated, and typically happens 15 to 30 minutes after every feeding.
The Most Common Cause in Infants
In newborns, projectile vomiting is the hallmark symptom of a condition called pyloric stenosis. The pylorus is the muscular valve at the bottom of the stomach that opens to let food pass into the small intestine. In pyloric stenosis, that muscle thickens abnormally, narrowing the opening until food can barely get through. The stomach responds by contracting harder and harder, eventually launching its contents back up and out with considerable force.
Symptoms typically appear between 3 and 6 weeks after birth and are rare in babies older than 3 months. Parents may notice visible wavelike ripples moving across the baby’s belly after feeding but before vomiting. These ripples are the stomach muscles working overtime trying to push food past the blockage. The baby is usually hungry again almost immediately after vomiting, because the food never made it into the intestines where nutrients are absorbed.
Doctors can often feel a small, olive-shaped lump in the baby’s abdomen during a physical exam. Ultrasound confirms the diagnosis by measuring the thickness of the pyloric muscle. In a healthy infant, the muscle is less than 2 mm thick. In pyloric stenosis, it can measure anywhere from 2 to 5 mm, and the pyloric canal itself stretches to 10 mm or longer, compared to under 5 mm in a normal stomach.
The fix is a minor surgery that splits the thickened muscle, widening the passage. Both open and minimally invasive versions of this procedure are safe and effective. With the less invasive approach, babies typically go home in 2 to 3 days, compared to about 6 days with the traditional open surgery. Complication rates are low, around 3% for the minimally invasive technique, and the condition almost never comes back.
Causes in Adults
In adults, projectile vomiting most often points to something physically blocking the exit of the stomach, a condition called gastric outlet obstruction. The most common benign cause is peptic ulcer disease, where ulcers in the lower stomach or upper small intestine swell and scar enough to narrow the passage. Long-term use of anti-inflammatory painkillers or infection with a specific stomach bacterium can both lead to this kind of ulceration.
Cancers can also block the stomach’s outlet. Stomach cancer accounts for up to 35% of gastric outlet obstruction cases, while pancreatic cancer is responsible for another 15% to 25%. In these situations, the tumor either grows into the passage from the inside or presses on it from the outside.
Food poisoning and severe stomach infections can occasionally cause vomiting forceful enough to qualify as projectile, though these episodes are usually accompanied by other symptoms like diarrhea, fever, and cramping, and they resolve within a day or two.
When the Brain Is the Cause
One of the more concerning causes of projectile vomiting has nothing to do with the stomach at all. When pressure builds inside the skull, whether from a head injury, a brain tumor, bleeding, or severe infection like meningitis, it can trigger the brain’s vomiting center directly. This type of vomiting is distinctive because it typically happens without any preceding nausea. You feel fine one moment and are vomiting forcefully the next.
Raised pressure inside the skull can also cause headaches that worsen when lying down, vision changes, and confusion. In infants, a bulging soft spot on the head is an important warning sign. This type of vomiting requires urgent evaluation because the underlying problem, not the vomiting itself, is the real danger.
Warning Signs That Need Immediate Attention
Projectile vomiting on its own warrants a call to your doctor, but certain additional symptoms turn it into an emergency. Green or yellow vomit contains bile, which means the blockage may be in the intestine rather than the stomach. A bowel obstruction is a medical emergency. Other red flags include severe abdominal pain, inability to pass gas or have a bowel movement, and being unable to keep any food or liquid down.
In babies, watch for signs of dehydration. Mild dehydration (around 3% to 5% of body weight lost) may show up as fewer wet diapers and a slightly dry mouth. Moderate to severe dehydration, above 6%, causes sunken eyes, skin that doesn’t bounce back when gently pinched, and sluggish behavior. Capillary refill, how quickly color returns to a fingernail bed after pressing it, slows down noticeably once dehydration becomes moderate. Any infant with repeated forceful vomiting after every feeding should be evaluated promptly, especially in the 3- to 6-week age window when pyloric stenosis is most likely to appear.
In adults, projectile vomiting that happens without nausea, comes with a severe headache, or follows a head injury should be treated as a potential neurological emergency. Repeated episodes over days or weeks, especially with unintentional weight loss, suggest a structural problem that needs imaging to rule out obstruction or malignancy.