Mice were monitored with pneumotachographs while they breathed emissions of three brands of disposable diapers (described herein as brands A, B, and C) and one brand of cloth diapers for 1 hr. The authors used a computerized version of the ASTM-E-981 test method to measure changes in the pattern and frequency of respiration. In response to two brands of disposable diapers, many mice exhibited reduced mid-expiratory airflow velocity, sensory irritation, and pulmonary irritation. During the peak effects, brand A caused sensory irritation in 47% of the breaths and reduced mid-expiratory airflow velocity in 17% of the breaths (n = 39 mice), whereas the respective percentages noted for brand B were 20% and 15% of the breaths (n = 28 mice). The effects were generally larger during repeat exposures to these emissions, with up to 89% of breaths showing sensory irritation in response to brand A and up to 35% of breaths showing reduced mid-expiratory airflow velocity with brand B. A third brand of disposable diapers caused increases in respiratory rate, tidal volume, and mid-expiratory airflow velocity. The emissions of cloth diapers produced only slight SI and slight PI. Chemical analysis of the emissions revealed several chemicals with documented respiratory toxicity. The results demonstrate that some types of disposable diapers emit mixtures of chemicals that are toxic to the respiratory tract. Disposable diapers should be considered as one of the factors that might cause or exacerbate asthmatic conditions.