Why are herbs important in orisa worship?

Osayin is the orisha of herbal medicine, healing, and magic. Osayin is the primary means of consecration in the Lukumí tradition as each plant has ashe within its leaves that are shared with the ashe of a particular orisha that we bring into physical manifestation. Herbs are usually used to prepare herbal elixirs known as omiero (cool or calm water) that is essential to harness ashe in most ceremonies. The preparation of omiero is accompanied by chants and prayers dedicated to Osayin.