I have heard of the Four Thieves mixture. It sounds perfectly harmless, so why not make it up or use it?
Do you know where to get hyssop?
Early last night, I posted a link for Mountain Rose herbs, might have sent it to you, they might have it.
There has always been an interest in the Thieves Vinegar, in 2001 an Essential Oil group was working it out in the oils and several other groups over the years have made it.
I see no harm in it, and history says it worked.
I always understood that the thieves wrapped cloths soaked in it over their faces for a face mask, so they did not breathe the germs, but those links said they take it, as a medicine.
I'm planting some in my garden this year. You can get hyssop heirloom seeds at VictorySeeds.com.