The doTERRA PB Assist probiotic defense supplement contains beneficial bacteria such as; L. acidophilus, L. salivarius, L. casei, B. lactis, B. bifidum, B longum, and a prebiotic made of fructooligosaccharides (FOS) for maximum digestive benefits. The PB Assist goes best with the GX Assist cleansing formula for the first 10 days so you can kick out the bad guys first and make room for the good ones!