OBJECTIVE: Exposure in connection with cleaning piggeries induces airway inflammation. The aim of this study was to compare the health effects related to two different cleaning processes in a piggery. METHODS: In a cross-over study design, 12 subjects were randomly exposed for three hours during the cleaning of a piggery with a high pressure water jet, with and without pre-cleaning using a robot. We assessed lung function, bronchial responsiveness, symptoms, body temperature, and exhaled nitric oxide, and performed blood sampling and nasal lavage before and after both exposures. RESULTS: Compared with ordinary cleaning without the use of a robot, pre-cleaning with a robot significantly reduced the increase in bronchial responsiveness (P=0.049), total cell number (P=0.0029), and pro-inflammatory cytokines (IL-8 level [P=0.016]) in nasal lavage, and diminished the increase in neutrophils (P=0.0029) in the blood. CONCLUSION: Pre-cleaning of a piggery with a robot reduced exposure to dust and endotoxin, and resulted in an attenuation of the increase in bronchial responsiveness and the airway inflammatory response compared pre-cleaning without a robot.