The handouts for some fencing classes I have taught over the years:

I had a bumper crop of blue elderberry this year so I made a huge batch of decoction of elderberry. Look at that purple color! Blue elderberry is a North American subspecies of the black elderberry that is native to Europe. Dioscorides has this to say about elderberry:

“A decoction (taken as a drink) helps those bitten by vipers. Boiled with water for bathing it softens the womb and opens the vagina, and sets to rights any disorders around it. A decoction of the fruit (taken as a drink with wine) does the same things, and rubbed on it darkens the hair.”

Maybe I will try using it as a hair dye.