If you’re a bit short of pocket money, you can now sell your poo to doctors in Medford, Massachusetts, in the USA.

The OpenBiome organisation is paying $40 for donations of poo, provided they are sure it has lots of ‘good’ bacteria.

You can even win a prize if you make the single largest donation each month! Unfortunately, you can only donate if you live or work near Medford.

We often think of bacteria as germs that make us sick, but some are good for us. If we don’t have enough good bacteria in our guts, then bad ones that make us sick can take over. Our guts extract the goodness from our food and discard the rest as poo.

One type of bad bacteria is called Clostridium difficile, known as C. difficile for short. It can cause diarrhoea, stomach pain and fever.

Mostly, if bacteria are making you unwell, a doctor might give you antibiotics, which kill the bacteria and make you better.  But the trouble with C. difficile is that the antibiotics might kill the good bacteria in your gut, and you want them.

Now researchers say that the best way to treat C. difficile infection is to get good bacteria from someone else and put them into the sick person by what they call a `faecal transplant’.

They take a little bit of poo from a healthy person with lots of good bacteria, and put it in the gut of the sick person. Then the good bacteria can multiply and crowd out the C. difficile, so the sick person gets better.  It’s over 90% effective.