It sells only food and drink that's additive-free and organic where possible - which means no artificial chemicals like colouring.
And the new items cost about the same or cheaper than the alternative options.
All Saints Catholic School and Technology College in Dagenham is one of those that's taken the plunge and installed the machine.
Even though it's next to the machine selling chocolate and crisps, it seems to be a hit!
Headmaster Desmond Smith explained: "The Green Machine is catching up with the others vending machines fast. The organic yoghurt is definitely popular."
If the trial is a success, the makers of the Green Machine hope to put it in schools across Britain.