Those of you trolling the streets of Manhattan in an allergy-induced haze may have stopped sneezing long enough to notice some curious fliers posted on assorted lampposts, scaffolding, and telephone poles around the city. The fliers, at right, are fashioned to look like the amateur handiwork of a sad little boy looking for information as to the whereabouts of his lost puppy. Upon closer inspection, though, they're actually a clever guerrilla marketing ploy from multi-billion dollar pharmaceutical company McNeil-PPC, makers of the over-the-counter allergy med Zyrtec. A representative handwritten ad reads: "MISSING. 2 HOURS. Last seen while waiting for Claritin to start working. If found please call 1-800-4-ZYRTEC." When the number is dialed, a chirpy female operator delivers the following message:

"You have reached the 'Missing Time' phone line. Looks like someone lost some time waiting for their Claritin to start working!" The operator then goes on to detail precisely why Zyrtec is better than the competition at curing your runny nose and itchy eyes.

Other people seem to have noticed the ads as well, and they've also been spotted in San Francisco and Boston. Have the fliers actually led to increased sales and name recognition of the drug, or have they just succeeded in getting people to talk about them on the Internet?

Hard to say: A McNeil spokesperson declined to give out statistics regarding the number of calls that have been logged, the name of the agency that conceived of the campaign, or even if the company got city permission to post fliers (it's technically illegal in most cities). When contacted a second time, a different spokesperson said that the company wasn't even familiar with the campaign. (So underground!) A few days later, we received the following email from a rep [WARNING: Frequent and obnoxious use of copyrighted product name ahead.]:

"A new advertising campaign launched in April highlights the fast acting nature of ZYRTEC®. The campaign reinforces the unique position of ZYRTEC®, which starts working faster than other OTC antihistamines. More than 35 million Americans suffer from indoor and outdoor allergies. This campaign is part of ongoing communication efforts by McNeil Consumer Healthcare, the markers of ZYRTEC®, to help people with allergies better understand allergies and what triggers them, and to highlight options available to allergy sufferers in managing their allergies more effectively. The company is committed to using a variety of communications vehicles to reach these consumers and their family members."

If nothing else, it's more effective than the Cartoon Network's grassroots marketing campaign in Boston last February, to be sure. [Via Cajun Boy]