A comparison was made in a laminar-flow operating room between total-body exhaust gowns and a clothing system made from Fabric 450. This disposable clothing was found to be much more comfortable and convenient than the total-body exhaust gowns. The average airborne bacterial counts obtained during total hip replacement operations from each of the clothing systems were identical when the downflow method of ventilation was used (0.7 per cubic metre) and no significant difference could be demonstrated when the crossflow system was used (2.2 per cubic metre with the total-body exhaust gowns and 3.1 per cubic metre with the disposable clothing). Tests in a dispersal chamber were carried out to find the effectiveness of each item of the disposable clothing in reducing bacterial dispersion. These tests demonstrated the relative ineffectiveness of wearing a surgical gown as compared with wearing the complete system. It was confirmed bacteriologically that the downflow system of ventilation was more efficient than the crossflow type; the importance of this observation with respect to clothing and sepsis is discussed in this paper.