Yes, I am a cancer survivor although I did not use chemo I have been at natural medical clinics where chemo patients do come and get iv vitamin c's and b's to improve their immune system. Also MGN-3 is very good for cancer patients. It will build the immune system very fast.Of course anything that a person uses should be ok'd by the attending physcian. Greens will help also. There are many greens to help the body system build. But I would first test the right herbs with an EDS testing sytem to find the right one for his or her body system. What may be right for one person may not be right for another person.EDS stands for Electral Dermal Testing. I hope that I have helped you.