Hi Corinne,
We source YBY at local Chinese herb stores here in Edmonton, or refer owners to them
As for vitamin AD, WDDC still carries it. It's not 500 000 IU per ml of vitamin A anymore, but 50 000 IU, with 5000 IU of vitamin D. It's made by Dominion Veterinary Laboratories in Winnipeg, if you're buying directly. Phone 1 800 465 7122
Steve