At-Tasrif liman 'Ajiza 'an at-Ta'lif (The Method of Medicine). At-Tasrif is a medical encyclopedia compendium of 30 volumes compiled from medical data that Al-Zahrawi accumulated in a medical career that spanned five decades of teaching and medical practice. It included sections on surgery, medicine, orthopedics, ophthalmology, pharmacology, nutrition etc.At-Tasrif contains many original observations of historical interest. In it, El Zahrawi elaborates on the causes and symptoms of disease and theorizes on the upbringing of children and youth and on the care of the aged and convalescent. In the section on pharmacology and therapeutics, he covers areas such as cardiac drugs, emetics, laxatives, cosmetology, dietetics, material medical, weights and measures and drug substitution.
At-Tasrif was translated into Latin by Gerard of Cremona in the 12th century and alongside Avicenna's Canon, played a major role as a medical text in the universities of Europe from the 12th to the 17th century AD. Two of El Zahrawi's treatises deserve special mention. Firstly his 28th treatise, known in Latin as Libber servitors de preparation Medici arum simplified, describes chemical preparations, tablet making, filtering of extracts and related pharmaceutical techniques. This treatise was printed in Venice in 1471 by Nicolaus Jensen.
Perhaps the most importance treatise is the one on surgery. This monumental work was the first in Arabic to treat surgery independently and in detail. It included many pictures of surgical instruments, most invented by El Zahrawi himself, and explanations of their use. There are approximately 200 such drawings ranging from a tongue depressor and a tooth extractor to a catheter and an elaborate obstetric device. The variety of operations covered is amazing. In this treatise El Zahrawi discussed cauterization, bloodletting, midwifery and obstetrics and the treatment of wounds. He described the exposure and division of the temporal artery to relieve certain types of headaches, diversion of urine into the rectum, reduction mammoplasty for excessively large breasts and the extraction of cataracts. He wrote extensively about injuries to bones and joints, even mentioning fractures of the nasal bones and of the vertebrae. In fact 'Kocher's method' for reducing a dislocated shoulder was described in At-Tasrif long before Kocher was born!
Once At-Tasrif was translated into Latin in the 12th century, El Zahrawi had a tremendous influence on surgery in the West.
In At-Tasrif, El Zahrawi expressed his concern about the welfare of his students whom he called "my children". He emphasized the importance of a good doctor patient relationship and took great care to ensure the safety of his patients and win their trust irrespective of their social status.
El Zahrawi's clinical methods showed extreme foresight - he promoted the close observation of individual cases in order to establish the most accurate diagnosis and the best possible treatment. He insisted on compliance with ethical norms and warned against dubious practices adopted by some physicians for purposes of material gain. He also cautioned against quacks who claimed surgical skills they did not possess.