RCT 5 Randomized double-blind, placebo-controlled clinical trial of 2 groups. 2-6 weeks old formula- and breast-fed colic infants (n=30), who cry without medical cause for 3h/d, for 3days/week, have been randomized to receive either placebo (microcrystalline cellulose) or a probiotic preparation (Lactobacillus rhamnosus GG, ATCC 53103) for 4 weeks. Formula-fed infants receive extensively hydrolysed formula and mothers of breast-fed infants avoid cow's milk in their diet.