"Sickle cell crisis" is a diagnosis made by exclusion, and infection must be ruled out as a cause of symptoms whenever a patient becomes acutely ill. Partial exchange transfusion is an important therapeutic tool, for it seems to interrupt "the vicious cycle of sickling" in some instances and forestall it in others. Child-bearing is an acceptable risk if the woman wants to raise a family, but oral contraceptives are probably safer than an undesired pregnancy. No drug is now recognized as an effective agent for prevention or termination of painful crises. Sodium cyanate and long-term transfusion need careful evaluation as means of treatment, but great care must be exercised to inform patients of both risks and benefits of any new regimen.