Abstract: A method of preventing pain in a sickle cell patient is disclosed. The method includes orally administering to the patient, an amount of an active agent effective on oral administration to inhibit binding of the patient's sickle erythrocytes to P-selectin on the patient's vascular endothelium. The inhibition may be evidenced in a number of ways. The active agent administration inhibits the adhesion of sickle erythrocytes to vascular endothelium in the patient, thereby preventing patient pain associated with vascular occlusion. Also disclosed are compositions useful in practicing the method.