Johnson & Johnson’s McNeil division recruited actor Neil Patrick Harris (of Doogie Howser and Dr. Horrible fame) to narrate a three-minute online documentary on the history and uses of Listerine.

An outshoot of the brand’s “Deepest Clean” TV campaign, it’s a genre-bender — part informational video, part gross-out and part horror movie. In a “Behind the scenes” clip at the campaign’s website, thisisyourmouth.com, Harris snarks that after learning all about how overrun with bacteria our mouths are, he’ll swish “two, maybe seven times a day.” The film also hints that not using mouthwash could lead to heart disease or diabetes.

“Emerging science suggests that advanced gum disease may be linked to other disorders, such as pneumonia, diabetes and heart disease,” says dentist John E. Dodes, DDS in the film, adding “Some studies have found oral bacteria in the arteries of people with heart disease.” At the end of the video, a disclaimer flashes on the screen, advising: “Emerging science suggests an association between periodontitis (advanced gum disease) and broader health problems, but a cause and effect relationship has not been established. Listerine Antiseptic has been indicated to help prevent or reduce plaque and gingivitis. It is not indicated for periodontitis or other diseases.”

For every viewing of the film, McNeil will donate a dollar to the Children’s Oral Health Foundation (“America’s Toothfairy”) up to $15,000. Edelman is handling PR for the film.