The pharmacologist of al-Andalus, born in Malaga and died in Damascus, Ibn al-Bayṭār (576/1180 or 583/1187–646/1248) composed a dozen works among which we must highlight: The Kitāb Mīzān al-Ṭabīb. The work presented here studies the only manuscript of this work that has been preserved, number 351 or Vet. 58 of the Universitetsbibliotek of Uppsala (Sweden) and describes the content of the same, a medical-pharmacological dissertation, divided into eighty chapters, each of which is dedicated to one or more diseases, going through all the organs of the body, starting with the head and ending with the feet.

The objective of this paper is the Arabic edition and the English translation of the Dissertation on thirst (الكلام في العطش), an anonymous text included in the miscellaneous manuscript nº 888 of the Royal Library of the Monastery of San Lorenzo de El Escorial in Madrid (Spain). This small treatise describes what thirst is, the types of thirst that exist, the causes why hydroponics are averse to water, the reason why diabetic people are continuously thirsty, the causes why people with fever are thirsty, the reason why some foods produce thirst and others do not, and so on. The whole manuscript is composed of fourteen works, written by the same copyist along 170 folios under the general title The book of medical and philosophical curiosities and utilities (كتاب النكت والثمار الطبية والفلسفية) and their subject are curious matters that are generally out of the span of most works on these two branches of knowledge.

Manuscript number 888 of the Collection of Arabic manuscripts of the Royal Monastery of San Lorenzo of El Escorial (Spain) contains a small treatise composed by physician and pharmacologist ʿĪsā b. Māssah al-Baṣrī (9th century). This work offers a detailed description of different causal agents that originate the sexual impulse and its culmination, the coitus. The treatise enumerates and interprets the physical factors that conform man’s sexual response, which is viewed as a purely physiological process, as well as the cultural and psychological factors that shape and modulate the sexual preferences of each individual.