As a cat seeks catnip, so Thor sought certain things when he was not feeling well.

All bitterness is not quinine, but certainly bitter things were Thor's remedies, and as he made his way up the gorge his nose hung close to the ground, and he sniffed in the low copses and thick bush-tangles he passed.
He came to a small green spot covered with kinnikinic, a ground plant two inches high which bore red berries as big as a small pea.

They were not red now, but green; bitter as gall, and contained an astringent tonic called uvaursi.

Thor ate them.
After that he found soap berries growing on bushes that looked very much like currant bushes.

The fruit was already larger than currants, and turning pink.