This interesting article makes the argument that if you introduce a large amount of foreign bacteria (good or bad), you are inducing an immune response and low-grade inflammation. It goes on to conclude:
a) Population studies will show an increased risk of heart attack, strokes, and pulmonary embolism as a consequence of the mild increase in the inflammatory state induced by chronic probiotics.
b) Infections will increase in the month or two after stopping chronic probiotics.
What do you guys think?