Scientific discoveries in recent years suggest that some serious conditions could be cured by adding “good” bacteria to your digestive tract. Now several companies are racing to develop drugs that do so.

It’s a jungle in there: massive populations of microbes, immune cells, and cells of the gut tissue are interacting and exchanging countless chemical and physical signals. Disruptions to this complex ecosystem, often called the microbiome, have been linked not only to gastrointestinal problems but also to metabolic, immunological, and even neurological disorders.

One such problem, which occurs when a very common species of bacteria, Clostridium difficile, colonizes the gut and becomes too abundant, can be cured by adding good bacteria to the digestive tract—but the method for doing so requires a transplant of another person’s feces, and the reasons it works are not well understood. The next generation of microbiome medicines will instead be “real drugs” that are “easy to take, clean, and safe,” says Roger Pomerantz, CEO of Seres Therapeutics.

Companies Aim to Make Drugs from Bacteria That Live in the Gut

Fermented food is good for your microbiome