Colic, or excessive infant crying, occurs during the first 3 months in approximately 15 to 20% of infants and is the most common concern for which parents seek medical advice during an infant's first year. Various physiological and environmental causes have been investigated. Some researchers have proposed multifactorial causes while others have argued that it is simply the extreme end of the normal crying continuum. As the etiology of colic is not clear, definitions of colic have relied on behavioral descriptions, and the relative merits of specific behaviors in affording an accurate definition are debated. This lack of clarity has compounded difficulties in identifying effective interventions for colic. One point of agreement is that colic is extremely distressing for parents. Some have argued that the disruption to the infant-parent relationship can have long-term implications for development while others have argued that only if the crying persists beyond 3 months is there a risk of long-term implications. It is concluded that due to the incidence of colic and the immediate impact it has on family functioning, more research is required to further our understanding of colic. In addition, the identification of effective coping strategies and consoling methods to assist parents through this stressful period is required.