What is Baby colic ?
Infant colic (also known as baby colic and three month colic) is a condition in which an otherwise healthy baby cries or screams frequently and for extended periods, without any discernible reason.
The condition typically appears within the first two weeks of life and almost invariably disappears, often very suddenly, before the baby is three to four months old . It is more common in bottle-fed babies, but also occurs in breast-fed infants. The crying frequently occurs during a specific period of the day, often in the early evening.
Since the cause is not conclusively established (see below) and the amount of crying differs between babies, there is no general consensus on the definition of "colic". Having ruled out other causes of crying, a common rule of thumb is to consider a baby "colicky" if it cries intensely more than three days a week, for more than three hours, for more than three weeks in a month.please concentration this is one cause of babies crying.
Article From : http://en.wikipedia.org/wiki/Baby_colic