The differential diagnosis of an elevated hematocrit and the criteria for the diagnosis of polycythemia vera present little or no problem; however, there is not a consensus on therapy. Spivak likened this to a conundrum--"an intricate and difficult problem." Nonetheless, it can be argued that on the basis of the following criteria--life expectancy, the absence of toxicity, and long remissions an average of 3.1 years or a median of 2 years--and with acute leukemia no more common than in other regimens except phlebotomy alone (a regimen that cannot be sustained), 32P should be the treatment of choice except in pregnant women. Others, but not all, share this view. This is in contrast to the statement, "Thus chemotherapy treatment of [polycythemia vera] patients is not as easy, innocuous, and well tolerated as it is generally believed". Patients treated with phlebotomy alone were subjected to an unacceptably high incidence of early thrombotic events. Unavailability of pipobroman eliminates this choice.