Colic is when a healthy baby cries for an extended period of time for no reason.
Colic typically begins suddenly with nonstop crying. This can be very stressful for mom and dad. The good news is colic will go away on its own after once the baby is around 3 months to 6 months old.
The cause for colic is unknown. Some theories include:
American Board of Pediatrics,
American Board of Pediatrics/Gastroenterology