Colic is a condition that affects infants and is characterized by frequent, prolonged, and intense crying or fussiness for no apparent reason. In general, colic is defined as crying for three or more hours a day, three or more days a week, for three or more weeks. Colic is most common during the first 6 weeks of life and usually goes away on its own by age 3 to 4. Babies with colic are healthy, eating, and growing well but cry in spells that happen at the same time of day. The cause of colic is unknown, but theories include immaturity of the bowel and the presence of "bad" bacteria in the gut. Intestinal colic is a different type of colic that is characterized by painful cramps in the abdomen due to a blockage in the large or small intestine.