Inclusion Criteria:

- Patients with refractory or relapsed: acute myelogenous leukemia (AML), and
myelodysplastic syndrome (MDS) (bone marrow blasts > or = 10%) are eligible.

- Untreated patients older than 60 years of age with AML or MDS (bone marrow blasts >
or = 10%) who refuse or are not eligible for front-line chemotherapy, are eligible.

- Performance status of < or = 2 by the Eastern Cooperative Oncology Group (ECOG)
scale.

- Signed informed consent indicating that patients are aware of the investigational
nature of this study in keeping with the policies of University of Texas M D Anderson
Cancer Center (UTMDACC).

- Age > 2 years. Valproic acid has been associated with a higher rate of severe liver
toxicity in children younger than 2 years.

- Patients must have been off chemotherapy for 2 weeks prior to entering this study and
recovered from the toxic effects of that therapy, unless there is evidence of rapidly
progressive disease. Use of hydroxyurea for patients with rapidly proliferative
disease is allowed for the first two weeks on therapy.

- Adequate liver function (bilirubin of < 2mg/dL, SGPT < 3 * Upper Limits of Normal
(ULN)) and renal function (creatinine < 2mg/dL).

- Women of childbearing potential must practice contraception. Men and women must
continue birth control for the duration of the trial.

- Patients with relapsed /refractory disease with inv16, t(8;21) or t(15;17) are
eligible.

Exclusion Criteria:

- Nursing and pregnant females are excluded.

- Patients with active and uncontrolled infections are excluded.

- Patients already receiving valproic acid or receiving other anticonvulsants will be
excluded.

- Untreated patients younger than 60 years will not be candidates for this study.

- Patients with untreated disease inv16, t(8;21) or t(15;17) will be excluded.