Parents and caregivers alike are frustrated by colic in infants. However, few randomized controlled trials evaluating the treatment of this condition have been conducted. Garrison and Christakis reviewed the literature to evaluate: the known treatments for colic, specifically simethicone, dicyclomine or methylscopolamine; a low-allergen diet for breast-feeding mothers or a hypoallergenic formula in bottle-fed babies; the use of soy-based or fiber-enriched formulas or treatment with lactase enzymes in bottle-fed infants; carrying the infant more often, using a car-ride simulator or training parents in behavioral approaches; and the use of herbal teas or sucrose.

A literature search of clinical trials and randomized controlled trials was conducted. The adequacy of case definitions and the methods used was evaluated to determine the quality of the trial. The Wessel definition (one that describes the frequency, character and duration of symptoms) was used as the ideal standard case definition. Diagnostic and outcome measures were recorded, although these tend to be subjective. When possible, the number needed to treat was used as the best way to evaluate the effectiveness of treatment.

Of the 53 articles identified, 22 randomized, controlled trials met the review criteria: eight dietary, seven pharmacologic, four behavioral and three naturopathic interventions. Methodologic weaknesses were evident in most of these trials, although nine had sufficient case definitions (41 percent used the Wessel definition), and 12 were adequately blinded.

Simethicone was studied in three trials, only one of which reported a possible beneficial effect. Other study results revealed no difference in the duration, frequency and intensity of crying, or in the number and frequency of the infant's stools. Simethicone has not been demonstrated to be an effective treatment for infant colic. Dicyclomine was found in three studies to be significantly better than placebo at reducing symptoms of infant colic. However, severe adverse effects were more common in those receiving the active medication, especially if they were younger than seven weeks. The manufacturer no longer believes dicyclomine to be appropriate for use in children younger than six months; in fact, it is contraindicated. Methylscopolamine was studied in one trial but showed no significant benefit when compared with placebo.

The studies following a hypoallergenic diet as a means of reducing colic in breast-fed infants are inconclusive. However, there is some evidence that a hypoallergenic diet (no milk, egg, wheat or nut products) is associated with a reduction in duration of colic symptoms. However, avoidance of cow's milk in the mother's diet did not seem to have any effect, except in women who had atopic conditions. Higher rates of colic were noted on days the infant received cow's milk compared with milk-free days. Hypoallergenic formulas reduced colic symptoms in bottle-fed babies, although the study was of low quality. Studies of soy-based formulas had some similar methodologic inadequacies, although soy formula seemed to be associated with a decrease in the duration of colic symptoms. Results from two randomized, controlled trials did not show lactase enzymes to be efficacious in the treatment of infants with colic.

Behavioral treatments for infant colic are difficult to study in an adequately blinded fashion. However, results from available studies do not appear to provide evidence of benefit from carrying the infant more often, using car-ride simulators, decreasing infant stimulation or training the parents intensively in a behavioral approach. In the latter case, there is not enough data on which to base a recommendation.

Results from one randomized, controlled trial revealed that after seven days of therapy, herbal teas (specifically one containing chamomile, vervain, licorice, fennel and balmmint) were associated with a decrease in the number of infants who still met the Wessel case definition. However, the authors caution against prolonged use of any substance that could lead to a decreased intake of milk with consequential nutritional adverse effects. A sucrose solution was associated with a reduction in colic-associated crying, but the effect seems to be very short-lived (a matter of minutes).