A consecutive series of 43 pyogenic granulomata in the oral cavity is presented. Most were located to the marginal vestibular gingivae and only a minority (12%) of these had a history of trauma whereas 70% in extragingival locations had a previous history of injury. On the basis of an evaluation of oral conditions the aetiology and the pathogenesis of the pyogenic granuloma are discussed. Trauma, microtrauma due to toothbrushing and gingival inflammation seem to be pathogenetic elements. It is suggested that the granuloma is a localised tissue response to a non-specific irritant.