a medicinal herb的用法和样例：
- Bilberry has been used as a medicinal herb since the 16th century.
- A medicinal herb with febrifugal and diuretic effects. The petal juice can be used as a dye for painting.
- A medicinal herb with febrifugal, anti-inflammatory, and diuretic effects; also used for relieving sore throat and tonsilitis.
- Iscador is made from mistletoe, which is poisonous under certain circumstances, but it has been used as a medicinal herb for hundreds of years in Europe, going back to the Druids.
- It sounds like a very good medicinal herb.