In Ezekiel 47:12, what were the leaves of the trees by the river used for?

Answer: Healing

Fruit trees on both banks bore fruit every month; their fruit was for food and their leaves for healing (KJV: medicine).

“Along both banks of the river, fruit trees of all kinds will grow. Their leaves will not wither, and their fruit will not fail. Each month they will bear fruit, because the water from the sanctuary flows to them. Their fruit will be used for food and their leaves for healing.””— Ezekiel 47:12 (BSB)