Rosemary (Rosmarinus officinalis) is an herb native to the Mediterranean region. The leaf and its oil are commonly used in food and also to make medicine.
Rosemary seems to increase blood circulation when applied to the scalp, which might help hair follicles grow. Rosemary extract might also help protect the skin from sun damage.
People commonly use rosemary for memory, indigestion, fatigue, hair loss, and many other purposes, but there is no good scientific evidence to support most of these uses.