[The sad picture of health: analysis of a billboard].

This article analyzes a billboard entitled "The Sad Picture of Health", displayed in the city of S o Paulo in May 1993. Based on various internal features and considering the surrounding social context, the billboard allows for two radically different interpretations. In the case of a such a "signed" billboard, such ambiguity implies a bad choice of the message intended to be conveyed by the sponsors. The author thus suggests that sponsors of such public announcements be aware of the ambiguity of their messages and forms of discourse.