Infants and toddlers in day-care centers have a relatively high frequency of diarrhea and/or oral antibiotic use, and may be at increased risk of developing diaper dermatitis when diapered. A six-month, prospective, double-blind study was conducted in day-care centers in Houston, Texas, to determine the frequency of diarrhea, antibiotic use, and diaper dermatitis in infants and toddlers wearing conventional (cellulose-only core) disposable diapers or disposable diapers with a core of absorbent gelling material (AGM) and cellulose. A questionnaire was administered weekly to the day-care staff to gather health information, and weekly visual examinations were made of children for diaper dermatitis. The frequency of diarrhea was 1.9 episodes per child-year and that of antibiotic use was 3.3 courses per child-year. Infants diapered in disposable diapers with AGM had a significantly (P 0.032) lower mean grade of diaper dermatitis during diarrhea episodes and a lower (P 0.054) mean grade during antibiotic use, compared to those diapered in conventional disposable diapers. There was no significant difference between groups with regard to isolation of Staphylococcus aureus or Candida albicans from superficial skin cultures of the diapered area. The results indicate that diarrhea and antibiotic use occur frequently in children in day-care centers, and that the severity of diaper dermatitis is less in children wearing AGM disposable diapers than those wearing conventional disposable diapers in that setting.