Objectives: Gaspar Casal (Gerona, 1680, Madrid, 1759) made most of his medical work in Oviedo (Asturias, Spain), where he lived for thirty-four years, before his return to Madrid as a doctor for the Royal House. Fruits of this work is the book "Natural and medical history of the Principality of Asturias" (Madrid, 1762), considered the best exponent of the Spanish medicine of the 18th century, and where the "disease of the rose", known later as pellagra or hypovitaminosis B, was first described in.
Methods: Study of the life of Gaspar Casal and analysis of "Natural and medical history of the Principality of Asturias", speculating on the knowledge about nephro-urologic and external genitalia diseases that can be deduced from the text.
Results: Casal knows and treats kidney lithiasis, relating it either to joint diseases and gout, or to dietetic excess and sedentary life in some of his patients. Other diseases coursing with poliuria and oedemas, are compatible with the nowadays diagnosis of infectious or degenerative nephritis. He rarely uses a bladder catheter for cases of stranguria and anuria, probably including some patients with anuria and others with urinary retention in the term "renal ischuria or high suppression", although he also uses the term "vesical ischuria" for the last ones. He treats the symptoms disuria-stranguria and haematuria, with empiric therapy, and, as it may be deduced from the text, some local surgeons didn't use or know to alleviate those symptoms with urethral catheterisation. He attends an epidemics of mumps, with orchitis in male patients, that were treated with bloodletting, although he stood against the misuse of phlebotomy in several diseases. Only occasionally he orders surgical treatment for several testis diseases.
Conclusions: "Natural and medical history of the Principality of Asturias" reflects the spectrum of diseases that conforms the day-to-day working schedule of a Spanish family doctor in the beginning of the 18th century, that is to say: diseases resulting from dietary shortage, infective, parasite, degenerative and vascular-cerebral diseases in older patients. From the nephro-urologic point of view, it is very interesting to read about the knowledge on stone diseases and lower urinary tract symptoms, that were treated as recommended by the classic authors, with physical therapy and empiric formulas, rarely with bladder catheterization. To a lesser degree, the results of the medical treatment of orchitis and the surgical treatment of some testis diseases are also depicted.