(HealthDay News) -- Although most babies spit up, forceful vomiting isn't normal and could be a sign of a digestive problem called pyloric stenosis.

The Nemours Foundation says warning signs of pyloric stenosis include:

• Projectile vomiting after a feeding, then wanting to eat again shortly afterward.
• Constipation, or stools that contain mucus.
• Not gaining weight.
• Being less active than a typical newborn.
• A ripple action that's visible on baby's tummy after baby eats.