Acidophilus is a friendly probiotic naturally found in the intestinal tract. Sundown's Acidophilus Xtra caplets can help you promote healthy functioning of your intestinal system and maintain a favorable balance of intestinal bacteria.* Acidophilus Xtra also supports a positive environment for the absorption of nutrients, and supports healthy immune function.* Sundown's proprietary XTRA Premium Blend provides 40 million colony-forming units at the time of manufacture