Background: Sickle cell diseases (SCDs) are inborn and destructive processes on vascular endothelium, particularly at the capillaries. Methods: All patients with the SCDs were included. Results: We studied 222 males and 212 females with similar ages (30.8 vs 30.3 years, p>0.05, respectively). Disseminated teeth losses (5.4% vs 1.4%, p<0.001), ileus (7.2% vs 1.4%, p<0.001), cirrhosis (8.1% vs 1.8%, p<0.001), leg ulcers (19.8% vs 7.0%, p<0.001), clubbing (14.8% vs 6.6%, p<0.001), coronary heart disease (18.0% vs 13.2%, p<0.05), chronic renal disease (9.9% vs 6.1%, p<0.05), chronic obstructive pulmonary disease (25.2% vs 7.0%, p<0.001), and stroke (12.1% vs 7.5%, p<0.05) were higher in males but not acute chest syndrome (2.7% vs 3.7%), pulmonary hypertension (12.6% vs 11.7), deep venous thrombosis and/or varices and/or telangiectasias (9.0% vs 6.6%), or mean age of mortality (30.2 vs 33.3 years) (p>0.05 for all). Conclusion: The sickled or just hardened red blood cells (RBCs)-induced capillary endothelial damage initiates at birth, and terminates with multiorgan failures and sudden deaths even at childhood. Although RBCs suspensions and corticosteroids in acute, and aspirin plus hydroxyurea both in acute and chronic phases decrease severity, survivals are still shortened in both genders, dramatically. Infections, medical or surgical emergencies, or emotional stress-induced increased basal metabolic rate accelerates sickling, and an exaggerated capillary endothelial edema-induced myocardial infarction or stroke may cause sudden deaths. Lifelong aspirin with an anti-inflammatory dose plus low-dose warfarin may be life-saving even at childhood both to decrease severity of capillary endothelial inflammation and to prevent thromboembolic complications in the SCDs. Key words: Sickle cell diseases, sickled or just hardened red blood cells, capillary endothelial edema, myocardial infarction, stroke, sudden deaths, low-dose warfarin