This invention relates to butyrate prodrugs derived from lactic acid and pharmaceutical compositions and methods employing them, either alone or in combination with other agents, for increasing gamma globin and fetal hemoglobin in a patient. These compounds, compositions and methods are particularly effective in treating .beta.-hemoglobinopathies, including sickle cell syndromes and .beta.-thalassemia syndromes. In addition, this invention relates to the use of these prodrugs, alone or in combination with other agents, to stimulate cell differentiation which prevents proliferation of malignant cells. These methods are particularly useful in treating cancer, especially malignant hematological disorders.