This is a prospective, observational study to collect stool and blood from acute myeloid leukemia patients undergoing intensive chemotherapy.

Inclusion Criteria:

• Adults (ages 18 - 99 years) undergoing inpatient intensive chemotherapy for newly diagnosed, refractory, or relapsed AML. Patients may or may not have been exposed to any type of therapy before.
• Any intensive chemotherapy regimen defined as a planned ~4 week inpatient stay. Chemotherapy may be delivered for any number of days and on any schedule. Patients may be discharged from the hospital sooner than 4 weeks if the treating physician choose so, but the expectation at the initiation of chemotherapy must be ~4 weeks of inpatient stay, as is typical.
• Able to provide written voluntary consent before performance of any study related procedure.

Adult patients with acute myeloid leukemia (new diagnosis, refractory, or relapsed) undergoing any intensive chemotherapy with expected inpatient stay of ~4 weeks.