An initial attachment of leucocytes to blood vessel walls is mediated by selectins. A feature of adhesion mediated by P-selectin is the "rolling" of leucocytes on the endothelium. The time dependent expression of p-selectin in lung tissue was investigated in five groups of cases with different causes of death: carbon-monoxide and cyanide intoxication (n = 11), drowning (n = 5), hanging (n = 9), pneumonia (n = 13) and polytrauma with blunt thorax trauma (n = 14). In paraffin-embedded archival specimens immunostaining was achieved using an adapted APAAP-immunoperoxidase technique together with a wet autoclave method. P-selectin detection was scored by a semiquantitative method evaluating the intensity and incidence of positively stained endothelial cells. The distribution pattern of endothelial P-selectin of blood vessels in cases of pneumonia and septic shock were heterogenius and weak. In one case with lung contusion (survival time 3 h) moderate infiltrates of granulocytes were found near to septal and subpleural hemorrhages. In these inflammatory areas the positive endothelial immunostaining of small vessels was often weaker than in other lung segments or compared to the intensely stained platelets in corresponding vessels.