The commonest question at the counter is which number to buy, and the commonest assumption behind it is that 200C is a stronger version of 30C the way 500mg is a stronger version of 250mg. It is not, and the difference matters for what you take home.
What the number describes
The C scale describes how many times the original material has been diluted one part in a hundred and succussed. A 6C has been through that six times; a 30C thirty; a 200C two hundred. So the higher number has less of the starting material in it, not more.
How that plays out in practice
In classical practice the higher potencies are generally used less often and further apart, and the lower ones more frequently. That is the practical difference you will feel: a 6C is a remedy you might repeat through the day, a 200C is one you take and then wait on.
Where to start
If you are buying for a household case and have no other steer, 30C is the standard: it is what our own 24-vial case ships at, and it is the potency most household guides are written around. Buy the 6C when a guide or a practitioner has told you to, and the 200C when you already know why you want it.
And if none of that resolves it, ring the shop. Working out which of two vials you need takes about four minutes on the phone and costs nothing.
