Do you... eat the tar? Put it on your skin? What exactly do you do with it?

Besides water proofing wooden boats and long time ago ships pine and fir tar it's been used protecting wooden roof tiles when they were a thing and still are used old wooden churches keeping and restoring.

It's used small amounts in additive in soap or shampoo mostly as a scent, mouth pastille and lozenge a for taste, animal health care kind antibacterial and bug resistant etc. long time ago.

Quite lot of applications especially old times long time ago before more scientifically developed medicines were commonly available. These days less there but it's used as a scent or for flavour.

I believe they were asking in the context of the quote at the start of the thread - "If liquor, tar and sauna won’t help, an illness is fatal."

I'm also still unclear on how it was used to treat human illness (treating boats and roofs is clear enough)