They aim to expand in drugs for multiple sclerosis and diarrhea-causing clostridium difficile, but regulatory approvals for those are years away.

But in randomized trials, the procedure has proved remarkably effective against potentially fatal infections of bacteria known as Clostridium difficile.

Currently, stool transplants -- which experts acknowledge come with a "yuck" factor -- are standard treatment only for virulent Clostridium difficile gastrointestinal infections.