The Effect of Chemotherapy on Red Blood Cells and Platelets

Blood is composed of several types of cell: red and white cells and platelets.

Chemotherapy acts on all the body’s cells and prevents them from multiplying. Those that multiply very fast, like blood cells, are the most affected and their number decreases.

This decrease varies: it may be slight or very considerable, depending on the different combinations of chemicals administered. Your blood cell count is checked very regularly by means of a blood test known as a ‘complete blood count’ (CBC).

Red blood cells (RBCs)

Red blood cells serve to transport oxygen in the blood. If their number is too low, this is called anaemia. It may cause fatigue and breathlessness when you make an effort. Your oncologist may decide to give you a blood transfusion to treat the anaemia.


Platelets or thrombocytes are one of the elements that make your blood coagulate (or clot). If there are too few, we speak of thrombopenia. If this condition is too serious, your oncologist may prescribe transfusions of packed platelets to lessen the danger of bleeding.

Some advice

  • Alert your doctor if you have any light bleeding: of the gums when brushing your teeth, blood in your stool or urine.
  • Go straight to the emergency service if the bleeding is persistent or heavy and ask that your oncologist be informed.
  • Note any bruises (haematoma) on your skin and point them out to your doctor.
  • When your platelet count is low, avoid activities where you may get knocked or fall.
  • Use cold or a light compress to stop bleeding while you wait for the doctor’s advice.

Download the sheet The effect of chemotherapy on red blood cells and platelets


Last update : 08/02/2019