The only one I've ever found is this one:
Heat 1.5 litres of water in a pan, when boiling add:
* 2 teaspoons fine ground dandelion root
* 1.5 teaspoons fine ground burdock root
* Inch square piece of root ginger
* 2 star anise
* Zest and juice of an Lemon
* Zest and juice of an orange
* 750g Sugar, I prefer using demerera or brown for the added flavour
In a pan simmer everything but the sugar for 20 minutes, then strain through a tea towel, muslin isn't really fine enough. Whilst the liquid is still hot you need to dissolve about 750g sugar. Adjust the sugar to taste. If you're finding the drink a bit flavourless simply add more sugar, it accentuates the flavours of the roots and anise.