Weill Cornell Bone Marrow Transplant Program

During Your Transplant

Conditioning Phase

Following the completion of your pre-transplant work-up, insurance approvals, and collection of cells, you will be admitted to the hospital to begin transplant chemotherapy — commonly referred to as the “conditioning regimen.” Before the stem cells can be given to you, your immune system must be properly conditioned. This is done with chemotherapy and/or radiation therapy, which also serves to eliminate any remaining disease. Your conditioning regimen is specific to your health status and the disease you are treating. Depending on your specific conditioning plan, this phase can take from 2 to 7 days.

There are various side effects of chemotherapy and/or radiation therapy. Some will appear quickly and disappear after several days, while others may occur more gradually and last for several weeks or months. These side effects will be discussed with you by your transplant physician; some of them include:

  • Nausea, vomiting and diarrhea
  • Fatigue, loss of appetite and hair loss
  • Organ dysfunction/failure, skin rash, mouth sores, and eye discomfort/sensitivity to light
  • Numbness and tingling of the extremities

It can be challenging to predict which side effects you may experience. You will be closely monitored for side effects. Our goal is to prevent or reverse side effects and to help you through this vital phase with as little discomfort as possible.


The chemotherapy given during the conditioning phase reduces the number of infection-fighting white blood cells in your body. Since your immune system is not functioning as it normally would, you are more prone to infections. The Transplant Unit is therefore HEPA-filtered for maximum infection prevention and control.
Personal hygiene is also essential. Performing proper hand hygiene with hand-washing or an alcohol gel or foam is a standard precaution. Depending on your condition and need for infection control, you may be asked to wear a mask, gloves, and/or an isolation gown when you leave your room. Visitors are also required to perform hand hygiene and any isolation precautions indicated by the Transplant Team.

The Transplant

The actual transplant is very similar to a blood transfusion. The previously collected stem cells, from either yourself or a donor, will be infused by a nurse through your catheter. This process can take from 1 to 4 hours. Your nurse will monitor your condition throughout the infusion.
Side effects of the infusion include, but are not limited to, excessive fluid accumulation in the lungs and/or an allergic reaction. These side effects are monitored closely and can be reversed.

Next: After Your Transplant