AIMS: To investigate the efficacy of chiropractic spinal manipulation in the management of infantile colic. METHODS: One hundred infants with typical colicky pain were recruited to a randomised, blinded, placebo controlled clinical trial. RESULTS: Nine infants were excluded because inclusion criteria were not met, and five dropped out, leaving 86 who completed the study. There was no significant effect of chiropractic spinal manipulation. Thirty two of 46 infants in the treatment group (69.9%), and 24 of 40 in the control group (60.0%), showed some degree of improvement. CONCLUSION: Chiropractic spinal manipulation is no more effective than placebo in the treatment of infantile colic. This study emphasises the need for placebo controlled and blinded studies when investigating alternative methods to treat unpredictable conditions such as infantile colic.