The prostitution is a thematic one excellent for the society and for the social work, and more in a near context as it is the city of Cali. The study presents a general panorama on the way how the official speech controlled the prostitution through the prevention of the venereal illnesses in the municipality of Cali at the beginning of the XX century, at the same time that shows how in the practice, the venereal danger would be a symptom auscultated by the official and progressively institutionalized speech and defined in the language of the medical treatment.