Thirty-six parents of colicky infants participated in this randomized, placebo-controlled clinical trial conducted via the Internet. Parents recorded a baseline state-of-arousal diary for 3 days using their usual feeding methods, and then they used six study-provided bottles for 2 weeks while recording a second state-of-arousal diary. Infants being fed with placebo bottles significantly spent more time crying (rho=.010) and fussing (rho=.002) on average than infants using Dr. Brown's Natural Flow Baby Bottles. Because these bottles decreased the time the infants spent crying and fussing, use of these bottles may be recommended for colicky infants who receive any bottle feedings.