Etiologic factors in the development of episodic diaper dermatitis include skin wetness and skin damage from fecal enzymes. In addition, when urine and feces mix, the activities of fecal enzymes increase as the pH rises from production of ammonia. An improved disposable diaper has been developed to provide better control of these factors by improved wetness and pH control. The improved diaper contains absorbent gelling materials (AGMs) blended into the diaper's cellulose core. AGMs are nontoxic, cross-linked polyacrylate polymers. They bind water tightly, give pH control by providing a buffering capacity, and in a diaper help to segregate urine and feces, thereby reducing the potential for increases in pH from ammonia production. To assess the effectiveness of this diaper, four 16-week clinical home-use tests were conducted with the AGM disposable versus conventional cellulose core disposable and home-laundered cloth diapers. Rigid group randomized stratification of infant maturity, diet, and initial level of diaper dermatitis provided control of factors other than the diaper that impact on development of diaper dermatitis. Skin wetness as measured by transepidermal water loss immediately after diaper removal, skin pH, and blinded visual evaluation of diaper dermatitis were used as skin condition measures. The use of AGM disposable diapers was associated with significantly reduced skin wetness and closer to normal skin pH as compared with the use of conventional disposable or home-laundered cloth diapers. Considered as an aggregate, the four clinical studies showed that AGM disposable diapers provide a better diaper environment and are associated with significantly lower degrees of diaper dermatitis than conventional disposable and home-laundered cloth diapers.