Neutropenia is a fall in the number of white cells in the blood.  The white cells help protect us from infections, so people who have neutropenia have a greater risk of getting an infection than the rest of us.

Most types of chemotherapy may cause neutropenia.  Usually this develops about a week after a treatment, it lasts for a few days, and then the white blood cells recover and the white cell count returns to normal.  Usually this temporary fall in the white cells causes no symptoms or problems and goes completely unnoticed. 

Sometimes however, the situation may be more serious.  This might be because someone is particularly sensitive to the chemotherapy, and has an unexpectedly severe fall in the number of white cells, or it may caused by the more intensive chemotherapy that is needed for some types of cancer. 

With the mild to moderate, temporary neutropenia, which occurs with most chemotherapy treatments, there is usually no need for any restrictions on, or changes to diet.  If the neutropenia is very severe however, there is a risk that some foods, which might contain bacteria or other germs, could lead to an infection.  At other times these foods would not cause any problems, but because the white cells are so low, the body's defences are greatly reduced, and a normally harmless part of the diet can become potentially harmful.

Live yoghurt does contain bacteria, and so it is a food that people with severe neutropenia should avoid.

In most cases people with severe neutropenia will be taken into hospital for treatment with antibiotics, and other supportive measures.  When this happens advice will automatically be given about the things that can, and cannot be eaten.

So the temporary neutropenia that happens with most chemotherapy treatments should not mean your mother would need to make any change to her diet. It would only be if her blood count dropped to very low levels that changes might need to be made.  Having said this, everyone is a little bit different, and it might be worth having a quick word with your mother's doctors, or chemotherapy nurses just to double check that it is OK for her to continue with her live yoghurt.