It is best to discuss probiotics with your doctor when taking immune suppressing drugs.

I have seen things written in the HIV/AIDs community that probiotics may cause sudden death or illness. Also a study was done on patients with acute pancreatitis given probiotics and some of those patients died too. This is because in the manufacture of probiotics there can be fungal contaminants present, which do not normally make people ill. But when the immune system is suppressed, they become pathogenic.

One way to get some beneficial organisms is to eat a quality yogurt. Ask your doctor if this is okay for you. I think it is a more natural way to do it. Stoneyfield has 6 organisms in their organic yogurts. But you can read the labels to compare which companies have a better content.

So it is best to ask your doctor. Anyone on immune suppressing therapy should be very careful and instructed on what they should do and what to avoid.