Abstract: The invention concerns a theft deterrent device (1), such as a tag, which is attachable to an article (3), to indicate the unauthorized removal of the article from a given area such as a retail establishment, said device comprising: at least one fluid (5)-containing member; a active staining substance (5) to be contained in said fluid-containing member; a housing (4) which encloses said fluid-containing member; means (6) for attaching the housing to the articles to be protected; means (7) for releasing the fluid from the fluid-containing member in response to unauthorised removal of the article, wherein the active staining substance in the fluid-containing member is a malodorous substance, and that said active substance subsequent to having impacted the article with the malodorous odour is capable of being neutralised by a corresponding counter substance.