Some doctors say using probiotics in a compromised immune system, like cancer, may not be good, even harmful, even though the good kind, believing it will be just adding more bacteria to fuel infection. If probiotics are taken, it should be the refrigerated type being they are live cells, and can be destroyed easily, if not handled, stored properly. I don't think yogurt is what they speak about, but more prescription or mega strength. I haven't met one doctor yet that said so, and every time I was in the hospital, yogurt was always on menu, and was even given probiotics for c-diff infection.