@service1010
I don't think that they will be as effective during radiation as they would be before and after radiation. FOS is a complex of fructooligosaccharides (FOS) - a group of naturally occurring carbohydrates that can help promote the growth of beneficial flora in the gastrointestinal tract. I first heard of FOS from an article in Science magazine that I fried gave to me. The article highlighted an animal study where FOS boosted good bacteria that reduced the population of bacteria that give rise to castrate resistant prostate cancer. I purchase my FOS from vitacost.com