Why was brown paper used of old for cuts and bruises?

I’ve come across this several times, most recently in Buckingham’s The Rehearsal, 1672, where Bayes taking a tumble and breaking his nose calls for ‘a wet piece of brown paper’ and then of course Jill in the nursery rhyme uses vinegar and brown paper to treat Jack.

What was the thinking behind this? Is this folk remedy still used anywhere?

it has a long history

and is still recommended by some

Probably it was the cheapest commonly available absorbent substance to make a poultice with. And it peels off fairly readily when dry.

Thanks to both, especially to Cub Mistress for those very informative links.

Is that like the roll of brown paper there used to be in butcher shops?

White paper would have been writing paper, which would be more expensive and less absorbent. Brown paper when wet would adhere to the skin and form a cheap, easily removable bandage in the days before adhesive Band-Aids.

Sort of, but modern brown paper is generally “kraft paper” made of wood pulp, which is thinner, smoother and more brittle than old brown rag paper, which in some cases was more like blotting paper. (Anybody still remember blotting paper?)

Historically, brown paper was a very coarse substance made from old rags, rope, canvas, and other relatively stiff fibres.