The objective of this study was to test whether the gastrointestinal tolerance of a new infant formula equalled or exceeded the tolerance of other milk-based infant formulas, and to compare the tolerance of the new formula to that of human milk. This prospective, observational, multicenter, open-label study was conducted in Taiwan. Healthy, full-term infants aged 28-98 days were enrolled on their current feeding regimen (no treatment assigned). Feeding regimens included human milk (HM), a new infant formula (NF, Similac Advance®), other marketed infant formulas (OF, mainly Enfalac® or S-26®), HM + NF and HM + OF. Data for stool frequency, stool consistency and gastrointestinal intolerance symptoms were recorded in study diaries by parents for a period of two weeks. Gastrointestinal tolerance was evaluated in 967 infants, of whom 481 (49.7%) received NF, 312 (32.2%) received OF, 101 (10.4%) received HM + NF, 41 (4.2%) received HM + OF and 32 (3.3%) received HM. Infants fed HM only had softer and more frequent stools than those who received NF only or OF only (P < 0.001). Infants fed NF only had softer stools than those fed OF only (P < 0.001), including those fed either Enfalac® or S-26® (P < 0.001). There were no significant differences between feeding groups for the incidence of general intolerance, spit-up or flatulence. All feeding regimens were well tolerated. We thereby concluded that NF is well tolerated in healthy infants and results in stool consistencies that more closely resemble those of infants fed human milk than those of infants fed other formulas.