The proper name is "faecal microbial transplant" and it is exactly what it sounds like.
But why would anyone want to do that and why are people doing it themselves?
Dr David Holland is one of the only people in New Zealand doing faecal transplants.
"You take a sample of normal faeces, usually from a spouse or close relative, and you make it into a kind of slurry then put it just a few centimetres into the patient's anus, then it's passed."
He says a key part of the digestion system is the gut and it's filled with good and bad microbes, so when you replace your poo with someone else's, it can change your insides dramatically.
It might seem like a disgusting idea but it's proving to have huge health benefits and a cure for certain gut conditions.
Story investigates just why these dirty specks are in fact very important in helping treat one particular disease.
Watch the video for the full Story report.