The interaction between leukocytes and endothelial cells is mediated by cell adhesion molecules. There are three families of adhesion molecules which play important roles in cell adhesion. They are integrin family, immunoglobulin superfamily and selectin family. The initial stage of adhesion is mediated by selectins and the firm adhesion is formed thereafter by the binding of CD11/CD18 complex with ICAM-1. Certain cytokines and inflammatory factors can induce cell adhesion mentioned above. The interactions among different adhesion molecules are very complicated. Antibodies directed at adhesion molecules, soluable adhesion molecules, oligopeptides with high affinity for the binding sides of the adhesion molecules, and some drugs can block the adhesion.