Avempace's book Kitāb al-Tajribatayn ‘alā Adwiyah Ibn Wāfid (Book of Experiences on Drugs of Ibn Wafid) is an attempt to classify plants from a pharmacological perspective. It is based the work of Ibn al-Wafid, a physician and Avempace's predecessor, and is said to have influenced the later work of Ibn al-Baitar, a prominent Arab pharmacologist and botanist.