The clinical picture of infantile colic, which usually starts within one month of birth, is that of a crying child who sleeps poorly at night. The cause of colic is uncertain. A variety of psychosocial and dietary factors have been implicated, however, and allergy to milk or soy probably is responsible for up to 20% of colic in infants. The infants are particularly susceptible to this allergy because of the immaturity of both their immune system and digestive tract. ...