Hydroxyurea is a cell apoptosis inducer that inhibit DNA synthesis through inhibition of ribonucleotide reductase. In Vitro: Hydroxyurea is used in a number of myeloproliferative, neoplastic, HIV, and non-hematological diseases^[1]. Treatment of cells in primary culture with 30 μM hydroxyurea for 96 hours significantly increases the fractional HbF content. The ^Gγ: ^Aγ-globin mRNA is induced 0.30- to 8-fold in vitro^[2]. Hydroxyurea has been shown to block HIV-1 reverse transcription and/or replication in quiescent peripheral blood mononuclear cells and macrophages^[3]. In Vivo: Hydroxyurea therapy producs consistent reductions in WBC and ANC without improvement in anemia over 17 weeks. Hydroxyurea at 50mg/kg produces a reduced white blood cell count, absolute neutrophil count and no improvement in anemia compared to vehicle treated sickle cell mice^[4].