gangreneA frame from the Health Department ad called “Amputation,” showing gangrenous toes. (Photo: New York City Department of Health and Mental Hygiene)

It wasn’t enough to show Ronaldo Martinez, who has to breathe through a hole in his throat as a result of years of smoking.

New York City health officials have taken their gross-out antismoking campaign one step further. They are in the midst of a three-week television blitz with a pair of the most gruesome and grisly advertisements in the city’s war against cigarettes.

The first ad, “Carotid,” depicts an operation to remove fatty deposits that had accumulated in the carotid artery of the brain. Doctors are seen opening a female patient’s neck and then extracting the fatty buildup, placing it on a surgical tray. Not every smoker will experience that kind of fatty buildup, but those who do are at twice as much risk of having a stroke as nonsmokers.

The second ad, “Amputation,” shows a patient on a table, with several toes withered away by gangrene. A doctor implies, through a drawing on the smoker’s leg, that the foot will have to be amputated — the result, a narrator says, of peripheral vascular disease, which puts smokers at much greater risk of gangrene and amputation.

Is there a limit to how disgusting a well-intended ad campaign can get? Our friends at the Freakonomics blog asked today whether such ads are effective and whether they are appropriate for viewing by children.

We asked those questions to Sarah Perl, the assistant commissioner for tobacco control at the city’s Department of Health and Mental Hygiene. Her answers: Yes and yes.

“We have seen an increase in calls and responses to this kind of hard-hitting ad,” she said. “Between January and June of 2006, we saw a 400 percent increase in the number of callers who reached out to 311 for assistance in quiting smoking.” A survey last year of 2,000 adults, conducted in August and September 2006 after the ad campaign began, showed that 9 in 10 smokers had seen the ads — and half said the ads made them want to quit.

“Based on that, we know clearly that these ads are reaching people and in a way that’s meaningful,” Ms. Perl said.

Ms. Perl, who has a daughter in third grade in Manhattan, said the mother of a schoolmate of the child approached Ms. Perl about the ads. “She said that when those commercials turn on, her kids want to tune in to them. It piques their interest.”

The two ads began airing on Aug. 27 and will continue through Sept. 16. They are being broadcast on region network and cable television channels, including sports channels.

The two ads were developed by Quit Victoria, an antismoking effort in the Australian state that includes Melbourne. One of the ads was redubbed for American audiences. The people depicted in the two ads are actors, except for one of the doctors in “Carotid,” who is played by an actual physician.

The city has emphasized that the alarming advertisements are only one element of its antismoking efforts, which include higher taxes on cigarettes, a ban on workplace smoking and the distribution of nicotine-replacement patches.