Bowel habits were assessed in 400 healthy Thai children aged 1-72 months. The study was undertaken principally because information concerning the bowel habits of children living on a non-Western diet is lacking. Ninety-four percent of the children moved their bowels at least once a day. Mean frequency of bowel actions per day was maximal in the newborn period (3.3 stools) and declined to once a day from ages of 48 to 72 months. Most infants younger than 2 months old produced running stools; however, a change in stool consistency from runny to formed was evident in most children by 4 months of age. With increasing age, children produced larger stools: mean volume of stool was 16.6 +/- 2.3 ml at 1 month of age and increased to 35.4 +/- 7.6 ml at 48-72 months. In comparison with Western children, it seems that Thai children pass larger, softer, and more frequent stools. That difference in the bowel habits between the two ethnic groups may reflect the difference in the amount of natural fiber in their diets.