Symptoms of Hirschsprung's disease vary depending on the child's age, when the symptoms are recognized, the amount of intestine affected, and whether complications are present.

In a newborn (birth to age 1 month), the major signs and symptoms include:

• A delay in passing the first stool (meconium) after birth. Healthy newborns usually pass stool within the first 24 hours after birth. A delay is common in Hirschsprung's disease.
• Constipation. The newborn does not have regular bowel movements.
• Vomiting.
• Refusing to eat.
• A swollen abdomen, which may cause the baby to breathe fast and grunt when breathing.

In an infant (age 1 month to 1 year), the major signs and symptoms include:

• Slower-than-expected weight gain.
• Constipation.
• A swollen abdomen.
• Episodes of diarrhea and vomiting.

In a child (age 1 year or older), the major signs and symptoms include:

• Constipation, with the passage of ribbon-like, foul-smelling stool or with large amounts of hard stool becoming stuck in and blocking the large intestine (impaction).
• A swollen abdomen.
• Poor appetite and poor growth.

Left untreated, Hirschsprung's disease can lead to serious, life-threatening complications. A child's small and large intestines may become inflamed, a condition known as Hirschsprung's-associated enterocolitis (HAEC). A hole (perforation) may then develop in the large intestine, causing stool to leak inside the abdomen. These complications require emergency surgery.

Other conditions with similar symptoms include a tumor or cyst on or in the intestines or a blockage that occurs when meconium becomes stuck in the baby's bowel (meconium plug syndrome).