Agency not known for its good taste.

Richard Zien has heard it all before.

Offensive. Vulgar. Needlessly provocative.

For years, the co-founder and president of Mendelsohn Zien Advertising LLC has confronted critics of his mid-sized ad agency with the verbal equivalent of a shrug.

So what if some people find his shop's commercials offensive? They work spectacularly.

And so it was in May when television stations began airing a spot for the Carl's Jr. fast-food chain featuring scandalous socialite Paris Hilton, clad in a black swimsuit while seductively washing a car before biting into an oversized hamburger. The ad ends with her signature line: "That's hot."

The Parents Television Council calls the ad "extremely graphic and sexually explicit" and is urging members to write letters of protest to Carl's parent company, Carpinteria-based CKE Restaurants Inc. Other cultural watchdogs say the ad represents a new low-water mark for taste in popular entertainment.

The Hilton ad is the latest brainchild of an agency that's built a successful business--more than $200 million in annual billings--largely on its ability to push buttons. Mendelsohn Zien's previous campaigns have employed, often humorously, such themes as cross-dressing, brutality and bisexuality.

Zien and business partner Jordin Mendelsohn make no apologies, saying their intent isn't to offend but to get their clients attention in a cluttered media environment. "We try to get our concepts to come to the edge of the table, but we don't want them to fail off," Zien said. "Paris Hilton, for our target audience, was enormously well received."

In your face

When Mendelsohn Zien was founded in 1984, its clients operated in a simpler and less cacophonous media world. But even in its early days, the firm showed a penchant for pushing the envelope of good taste.

A campaign for the Chinese restaurant Wok Fast in the early 1990s brought threats of a lawsuit from then L.A. police chief Daryl Gates, whose photo was juxtaposed on a billboard with the slogan, "When you can't leave the office or won't"--a reference to Gates' refusal to step down from his job. Wok Fast pulled the plug on another Mendelsohn Zien ad--"Just what L.A. needs: More Chinese drivers"--after Chinese-American groups protested.

The agency also produced racy spots for the clothing company Clothestime Inc. One showed a man getting excited at the sight of a woman and another portrayed a cross-dresser. The ads weren't enough to save Wok Fast or Clothestime, both of which are now defunct.

But Mendelsohn Zien was credited with helping revive BMW in the mid-1990s amid heavy competition from Toyota's luxury nameplate, Lexus. In a campaign unusually bareknuckled by the standards of luxury consumer advertising, BMW savaged Lexus as Toyota by another name and price.

Zien and Claudia Caplan, chief marketing officer for Mendelsohn Zien, said the agency specializes in companies that need a splash--both in their product line and advertising approach.

"It's very easy in this business to do the advertising equivalent of flashing someone, but it's not very strategic," Caplan said. "We tend to get the ICU patients. We are not a maintenance agency. We tend to do very well with the clients who have the most acute needs."

Even before the Paris Hilton spots, Mendelsohn Zien's approach was getting noticed in local and national advertising circles, both positive and negative. Ad consultant Larry Londre counts himself as a fan. "Right now they're hot, they're creative and they're moving the needle," he said.

As a privately held company, Mendelsohn Zien does not disclose revenue or profits. But the firm--which is partly owned by the Japanese advertising conglomerate Hakuhodo Inc.--did release data showing that its gross billings surged to $225 million in 2004 from $130 million in 2001. To some extent that increase reflects a post-Sept. 11 rebound in commercial advertising, but Mendelsohn Zien's growth eclipses the industry average. Estimates of their current revenues are $13 million to $15 million.

Mendelsohn Zien's principals see themselves as turnaround artists--able to take a foundering brand, work with the executives to rescue it and then unveil attention-getting ads intended to show how things have changed.

One example is Hardee's, the East Coast-centered fast-food chain also owned by CKE that by 2001 was in the throes of an identity crisis and lagging sales. (CKE is Mendelsohn Zien's largest client.) The agency persuaded Hardee's executives to streamline the chain's sprawling menu and focus on hamburgers--specifically those with 100 percent Angus beef.

With burgers as Hardee's raison d'etre, Mendelsohn Zien created a series of ads that turned heads--not for racy content, but for admitting that Hardee's previous approach had been a failure. In a number of stark black-and-white television spots, customers disparaged the restaurant, then expressed surprise that the food actually had become good. The tagline: "The last place you would ever go for a burger will become the first."

"We didn't have to be food experts," Zien said. "But what we know from doing our research and understanding consumers is when a product is not performing. Most agencies don't want to go to their clients and tell them their product is not good enough. We will."

The Paris Hilton ads have generated enormous free publicity for Carl's Jr., including articles in the Los Angeles Times and USA Today, and a special on "Entertainment Tonight." It also drove an unprecedented number of users to Carl's Jr.'s Web site and a separate Web site set up exclusively for the Paris Hilton ad.

But there's no solid evidence that it's pumped up sales at the 1,014 owned or franchised Carl's Jr. restaurants or for the particular sandwich Hilton was hired to promote, the Spicy BBQ Six Dollar Burger.

Carl's Jr.'s same-store sales increased 1.5 percent in the four-week reporting period ended May 23, compared with the like period last year (the Hilton ad began airing May 17). Indeed, some marketing experts expressed skepticism that the publicity would translate to significantly higher sales.

"This is a desperate attempt to get attention," said Michael A. Kamins, an associate professor of marketing at the Marshall School of Business at the University of Southern California. "It could backfire on (Carl's Jr.) because it's not mainstream. It could irritate people and get them ticked off."

Harvey Farr, president of the Farr Marketing Group in Los Angeles, said he doubts the ad will generate any backlash but noted that there's no clear connection between the scantily clad Paris Hilton and the hamburger she's promoting.

"The commercial is so over the top that I don't know that people are going to remember that it's for hamburgers," Farr said. "When you do a commercial, you have to have the goal of selling a product."

But executives at CKE, which reported fourth-quarter net income of $7.1 million, compared with a net loss of $51.7 million a year earlier, say the commercials have a larger goal: positioning Carl's Jr. as the most testosterone-fueled burger chain, ahead of milder rivals such as McDonald's and Burger King.

It's not a new approach. Since 1995, Mendelsohn Zien has produced ads for Carls' Jr. featuring a man and a woman undressing after staining their clothes with condiments, a woman eating a hamburger while gyrating on a mechanical bull, and numerous macho men messily sinking their teeth into beef patties.

"This ad, probably more so than many of the ads, is probably a more subtle sell in terms of a specific product," said Brad Haley, CKE's executive vice president of marketing. "For this target audience, they're a savvy group of consumers. These young guys have been exposed to millions of advertising messages on TV and on the Web."