Microbiome treatments are taking off

In a small laboratory at Guy’s and St Thomas’ hospital in London, Désirée Prossomariti is processing donations. Each is weighed, tested for pathogens, filtered, centrifuged and then freeze-dried, before being turned into a powder to be encapsulated and given to patients. The process takes a strong stomach, for the donations are of fresh faecal matter. “I don’t smell it any more,” says Dr Prossomariti.

The lab workers are not interested in the faeces themselves, but the tiny organisms they carry. Scientists have long known that the guts of animals, including humans, are full of bacteria, viruses and other micro-organisms. But it is only recently that they have come to understand just how important they are. Far from a collection of mere passengers, the microbiome is a vital part of a healthy body. Its members help break down food, produce chemicals that regulate the body within which they live, and repress the growth of other, harmful species of bacteria.