It is a soil based probiotic that contains bacteria not normally found in the human gut. It won't colonize (stick around) the gut. However I think it is good in killing pathogens (bad bacteria and yeast) in the gut. It does have bacillus subtilis which does attack candida. I personally did not have dramatic results using it (I still take it). It is somewhat expensive so if someone is of modest means I don't think it is a critical supplement that must be taken. However, I know of people who did have wonderful results using it probably because their dysbiosis was different and more complicated than mine. I think Three Lac is more beneficial to candida sufferers than Prescript-Assist.