Medical Oncologist
Blood counts
A low haemoglobin during chemotherapy
Chemotherapy works on fast-dividing cells, and the marrow that makes red blood cells is one of the fastest-dividing tissues in the body. Fewer red cells means less oxygen carried, so everything takes more effort — that bone-deep tiredness is different from ordinary fatigue. It is common, measurable on a blood test, and treatable, which is why it should not simply be accepted as part of treatment.
NG
Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
17+specialists on panel
15,000+patients treated
35+centres across Telangana & AP
4.8★ / 800+Google rating
The short answer
Why does the haemoglobin fall during chemotherapy?
Because chemotherapy works on fast-dividing cells, and the bone marrow that makes red blood cells is one of the fastest-dividing tissues in the body. Fewer red cells are produced, so the haemoglobin drifts down over the course of treatment.
Red cells carry oxygen. When there are fewer of them, everything takes more effort — climbing stairs, carrying a bag, sometimes just talking for a while. That is the tiredness people describe as bone-deep, and it is different from ordinary fatigue.
Why it matters that you mention it
Because it is routinely dismissed, by patients and sometimes by families, as the tiredness everyone expects from chemotherapy. A low haemoglobin is common, it is detectable on a blood test, and it is treatable. Being exhausted for weeks when something could have been done is a waste.
Ask what your haemoglobin was at the last blood test. It is checked before every cycle and you are entitled to know.
!
Go to hospital the same day
Breathlessness at rest, or on very little effort · chest pain or tightness · a racing or pounding heartbeat that will not settle · fainting, or feeling you are about to · confusion or unusual drowsiness · a fever alongside any of these · black tarry motions, blood in the motions or vomit, or any heavy bleeding. Go to the nearest emergency department and say clearly that the person is on chemotherapy. A rapid drop from bleeding is a different and more urgent situation than a slow drift downwards.
Not sure whether this applies to you?
Ask an oncologistWhere it comes from
Why the level falls, and why the cause matters
Usually more than one thing at once. Which ones apply to you decides what is done about it.
The treatment itself
The commonest reason. The marrow is suppressed by the drugs and makes fewer red cells, so the level drifts down across cycles and recovers after treatment ends.
Typically
- Gradual rather than sudden
- Deepens over successive cycles
The cancer itself
Some cancers lower the haemoglobin directly, particularly those affecting the marrow, and some cause slow blood loss. This is one reason a low level is investigated rather than assumed.
Bleeding
Slow loss from the stomach or bowel, heavy periods, or bleeding from piles. This matters because the treatment is completely different, and because platelets may be low at the same time.
Black tarry motions or blood anywhere should be reported the same day.Eating very little
Poor intake over weeks contributes, though it is rarely the main cause during chemotherapy. Food helps at the margins rather than fixing a treatment-related fall.
Kidney changes
The kidneys make the hormone that tells the marrow to produce red cells. Where treatment has affected kidney function, that signal weakens and the level falls further.
Something separate
A shortage of iron, vitamin B12 or folate, thyroid problems, or a long-standing condition unrelated to the cancer. Blood tests sort these out, which is why the cause is checked rather than presumed.
What is done about it
The options, and who decides
The first step is always to find out why, because the treatment depends entirely on the cause. A level that is low because of bleeding needs the bleeding dealt with; a level low from marrow suppression needs something else altogether.
Watching and waiting
Where the level is only mildly down and you feel reasonably well, often nothing is done beyond checking it before each cycle. The marrow usually recovers between cycles and fully after treatment ends.
Transfusion
Where the level is low enough or the symptoms significant enough, transfusion raises it quickly and most people feel noticeably better within a day. That decision belongs to your treating team, who weigh the number, your symptoms, your heart and what is coming next in your treatment.
Injections that stimulate the marrow
In some situations, medicines that prompt the marrow to make more red cells are used instead of transfusion. They work slowly rather than immediately, they are not suitable for everyone, and whether they are appropriate is a specialist decision.
Treating what else is contributing
Replacing a genuine shortage of iron, B12 or folate if tests show one. Dealing with bleeding. Adjusting medicines that are making things worse. This is where a proper investigation earns its place.
Nothing here should be used to start, stop or change a medicine. Do not begin iron or any supplement without your team seeing your results.Day to day
Managing while the level is low
Pace rather than push. Do the important things at the time of day when you have most energy, and accept that the list will be shorter than it used to be. Fighting it produces exhaustion without achieving more.
Move slowly between positions
Sit up before standing, and stand for a moment before walking. Dizziness on standing is common with a low haemoglobin and falls are a real risk, particularly in older people and particularly at night.
Keep eating and drinking
Protein at most meals and steady fluids help how you feel even when they cannot fix the underlying level. Dehydration makes dizziness and tiredness considerably worse and is easily avoided.
Gentle activity still helps
Short walks, within what you can manage, reduce the deconditioning that makes everything harder. Complete rest for weeks weakens muscle and makes the tiredness feel worse. Ask your team what is reasonable for you.
Tell people what you can actually do
Families frequently misread this tiredness as low mood or as giving up, and push in unhelpful ways. Explaining that it is a measurable blood problem rather than a state of mind usually changes how the household responds.
Report worsening breathlessness rather than adapting to it. People quietly reduce their activity until the problem is invisible.Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Being straight with you
What this page cannot tell you
It cannot tell you what your level is or what should be done about it. There is no single figure at which action is taken — it depends on your symptoms, your heart and lungs, how fast the level fell, and what treatment is planned next. Two people with the same number can quite properly be managed differently.
It also cannot tell you whether iron or any supplement would help. A low haemoglobin during chemotherapy is usually not caused by a shortage of iron, and taking iron when it is not needed causes constipation and can be harmful. That decision belongs to your team, after tests.
What to do next
Ask what your haemoglobin was at the last check and whether it is falling. Describe your symptoms specifically — what you can no longer do that you could a month ago. Report breathlessness rather than adapting to it. And if any of the emergency signs are present, go in today.
Questions we are asked
Common questions about a low haemoglobin
Is a low haemoglobin expected during chemotherapy?
It is common, because the marrow that makes red cells is suppressed by the drugs. Common is not the same as ignorable — it is measurable, treatable, and often the reason someone is exhausted. Ask what your level is rather than assuming the tiredness is simply part of it.
Will it get better after treatment?
For most people yes, as the marrow recovers once the drugs stop, though it is usually gradual over weeks to months rather than quick. A level that stays low well after treatment has finished should be investigated rather than accepted, as something else may be contributing.
Should I take iron tablets?
Not unless tests have shown you are actually short of iron. A low haemoglobin during chemotherapy usually comes from the marrow being suppressed rather than from a shortage of iron, and taking it unnecessarily causes constipation and can be harmful. Let the tests decide.
Will eating beetroot and dates fix it?
They are perfectly good foods and they will not correct a treatment-related fall. Diet helps at the margins. It is worth eating well for many reasons, but relying on food instead of reporting symptoms is how people stay exhausted for weeks unnecessarily.
Does a low level mean the treatment is working?
No. Blood counts reflect the effect of the drugs on the marrow, not their effect on the cancer. Whether treatment is working is judged on scans and tests. People with mild count changes and good results are common, and so is the reverse.
Will my cycle be delayed because of it?
Possibly. Counts are checked before every cycle and treatment goes ahead only if they are in a safe range. A delay for this reason is a considered decision that protects you, and most people resume once the level recovers or is corrected.
Why am I breathless when I was not before?
Fewer red cells means less oxygen carried, so the body compensates by breathing harder and the heart beats faster. Report it rather than adapting. Breathlessness at rest, chest pain or a racing heart that will not settle need an emergency department the same day.
Is a transfusion dangerous?
It is a routine and closely monitored procedure, with blood carefully matched and checked beforehand. Reactions happen and are usually mild and quickly managed. Whether you need one is a decision for your treating team based on your level, your symptoms and your overall situation.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Patient stories
Hear it from people we have treated
Every story is a video, in the patient's own words. Nothing here is a written testimonial.
Sources
- Cancer Research UK — Cancer drugs side effects
- National Cancer Institute — Chemotherapy and You
- Macmillan Cancer Support — Low red blood cell count
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Talk to us
Exhausted in a way that feels different?
Tell us what has been found so far and we will help you reach the right specialist. One helpline serves every CION centre.