Purpose: To determine whether salvaged autologous blood collected postoperatively contains complement split products (SC5b-9), and pro-inflammatory cytokines (IL-6 and IL-8) and whether there are any differences between blood collected during hip or knee surgery.Methods: Fifty-eight consecutive patients undergoing hip or knee replacement surgery were studied. Thirty-eight had postoperative bleeding large enough to require infusion of salvaged blood. The salvaged blood was filtered during collection through a 200 µm filter and before infusion a 40 µm filter was used. Samples for complement and cytokine determinations were drawn from the circulation and from the collected blood.Results: High concentrations of SC5b-9, IL-6, and IL-8 were found in salvaged blood. The concentrations were higher than in the circulation (P < 0.05). The circulating concentrations of IL-6 and IL-8 were increased 60 min and 12-18 hr after transfusion. There were no differences regarding SC5b-9, IL-6, and IL-8 in the blood collected after hip or knee surgery.Conclusion: Blood collected from a surgical wound contains large concentrations of inflammatory mediators. There were no differences between blood collected during hip or knee surgery.Objectif : Déterminer si la récupération postopératoire de sang autologue contient des produits de dégradation du complément (SC5b-9) et des cytokines pro-inflammatoires (IL-6 et IL-8), et s'il y a des différences avec le sang prélevé pendant l'opération de la hanche ou du genou.Méthode : L'étude a porté sur 58 patients successivement admis pour la mise en place d'une prothèse de hanche ou du genou. Chez 38 d'entre eux, les pertes sanguines postopératoires ont été assez importantes pour néces-siter la transfusion de sang récupéré. Ce sang a été filtré pendant le prélèvement avec un filtre de 200 µm et avant la transfusion avec un filtre de 40 µm. Des échantillons retenus de la circulation et du sang récupéré ont servi à déterminer la cytokine et le complément.