In his encyclopedic work on surgery, diseases, and their cures, al-Zahrawi devoted much attention to the healing properties of duhn, oil extracted from various natural substances. His list includes:

The Duhn of Bitter Almond: if mixed with wine arid applied to the scalp will be useful against open sores and dandruff therein.

The Duhn of Sweet Almond: is soothing to the chest and lung. It also dissolves hard tumors and relaxes spasms everywhere.

The Duhn of Laurel: helps to widen the opening of the veins. It relieves pain of the organs as well as chills, ear aches, and headaches.

The Duhn of Wheat: is hot and helpful in stopping ringworm at the start. Rub the ringworm with course cloth until it is almost going to bleed, then apply the Duhn on it. Repeat the same procedure until it is healed—God the...