In my search, I came across a very interesting research study by pediatricians Thomas Metcalf and colleagues in the peer-reviewed journal Pediatrics (Simethicone in the treatment of infant colic: A randomized, placebo-controlled, multicenter trial, Pediatrics, 1994, vol 94(1), 29-34, by Metcalf, Irons, Sher, & Young; PMID: 8008533). These researchers conducted a randomized, double-blind, placebo-controlled study. This is a fancy way of saying that participants (the babies) were randomly assigned to a group that received simethicone or a placebo (a substance that is not expected to have the therapeutic properties of simethicone) and no one knew until the end of the study to which group each baby was assigned. This type of design maximizes the chance that any differences between the simethicone and the placebo are due to the effects of the simethicone.
The researchers1 examined 83 infants over the course of 3 to 10 days, during which time the infants received either liquid simethicone (a chemical defoaming agent) or a placebo matched to Mylicon in taste, smell and odor. Parents filled out diaries to record their infants' behaviors, such as the severity of fussiness and crying. Statistical analyses of the parents' responses demonstrated that simethicone was no more effective than the placebo in reducing episodes of colic. In fact, numerically speaking the parents whose infants consumed simethicone were more likely to report worsening of colic than those parents whose infants consumed the placebo.
1Metcalf, T. J., Irons, T. G., Sher, L. D., & Young, P. C. Simethicone in the treatment of infant colic: A randomized, placebo-controlled, multicenter trial. Pediatrics, 94, 29-34.