The effect of Simethicone on "colicky" (n = 27) infants was tested in a double-blind cross-over study. Three different parameters were used to measure the efficiency of the treatment: interviews, 24-hour records and behavioral observations. No effects of Simethicone on the symptoms of infantile colic could be demonstrated. However, 67% of the infants improved during the treatment, which could be ascribed to a high-grade placebo-effect.