The initiative is billed as the first image campaign in the company's history and comes as the embattled firm continues to face fallout from the Vioxx recall.
'We believe it is important for people to know who we are,' said director of media relations Chris Loder.
WPP agency Ogilvy & Mather (O&M) has already secured the advertising component of the campaign, launched this month, which will run until the year's end.
Loder said the themes and messages of the PR campaign would be consistent with O&M's advertising.
Merck executives first took a closer look at the firm's reputation in January 2003, according to Loder. The company then contacted 20,000 stakeholders to find out what they knew about Merck - it turned out that fewer than half of lay and medical audiences were 'somewhat' or 'very' aware of the brand.
In addition to its own challenges, Merck has been caught up in the reputational problems facing the entire drugs industry. Rival companies, such as GlaxoSmithKline and Bayer, have launched similar campaigns.