Which is uglier? The fact that Methane is found in dog poop and cigarette smoke, or that Urea is found in cat pee and cigarettes?
This anti smoking ad takes a serious shift in tone from meaningless poop jokes. There may be some uncomfortable chuckling, but the the viewer is aware of two major facts:  methane, a chemical in dog poop, can be found in cigarette smoke and  urea, a chemical in cat pee, is also used in cigarettes.
Arnold Worldwide and truth, an anti-smoking organization, produced a 30 second ad to heighten awareness on the ugliness of smoking. Take a look and see if you would pick up a cigarette after watching?
Read about the strategy for raising awareness on the truth website. They don’t tell people to stop smoking, because they know that sort of pitch doesn’t work on little children, let alone addicted smokers. So, they appeal to their target audience with alternative methods, such as disgusting facts.
Stripping away moralistic lecturing in favor of poop jokes might just be bizarre enough to catch someone’s attention.