The development of new techniques for isolation of neutrophils extravasated in vivo have been essential for studying the dynamics of the inflammatory response in humans. Methods for generating inflammatory skin reactions were first presented in the mid 1950s, and later a skin blistering technique based on suction was introduced. With this procedure, small areas of denuded dermis, called "skin windows", are created and covered with special chambers containing a medium that attracts exudated neutrophils. By comparing the neutrophils collected in such chambers with those isolated from peripheral blood, it is possible to investigate the functional modifications that neutrophils undergo when attracted to an inflammatory process. The skin-blister chamber technique represents an aseptic, non-traumatic and reproducible model of inflammation that can be used to study in vivo activated human neutrophils. The background, methodological aspects and options of this technique are described, together with the functional characteristics of exudated neutrophils. (C) 1999 Elsevier Science B.V. All rights reserved.