I have lived through a variety of health fads, so color me skeptical of the hot new thing. One of the latest is probiotics, a group of substances that are supposed to be helpful for all kinds of bowel ailments as well as allergies, tooth decay, colds, etc.
Some people also take probiotics following a course of antibiotics, in hopes of restoring "good" bacteria to the gut.
According to the National Center for Complementary and Integrative Health (a division of the U.S. Department of Health and Human Services), more research needs to be done on probiotics before anything definitive can be said about their efficacy.
Their page is really helpful.
I eat yogurt a few times a week because I prefer to get my calcium from food rather than pills and because I am mildly lactose intolerant. (Yogurt in small amounts doesn't bother me.) Yogurt contains lactobacillis, one type of probiotic. (Bifidobacterium is the other.)
I have never had ill-effects from lactobacillis in yogurt. That's because eating yogurt or some other fermented food that naturally contains probiotics is not the same as frontloading these substances through supplements, which usually give you a megadose.
If you are thinking about taking probiotics supplements, be aware that they may cause unwanted side effects such as infections in people with weakened immune systems--and that includes any of us taking chemo like hydroxyurea.
Bottom line: I'm not trying to create a scare here, only urging you to talk to your doctor before you start taking any supplements. Be ready to explain why you think the probiotics would help you and discuss dosing.
Meantime, enjoy your yogurt and be well!