Gaithersburg officials are concerned that their attempt to ban the sale of the cheap, highly potent wines they believe are favored by the city's homeless alcoholics is not getting a fair chance at success because a new fortified wine, Cisco, has made its way onto store shelves.

Cisco, which has one of the highest alcohol levels of any of the cheapest wines on the market, has been available for nearly five years in the District and throughout much of the country, but began appearing in Montgomery County stores this summer.

Now, Gaithersburg officials are calling on store owners who have agreed to the four-month-old voluntary ban on four other wines to also include Cisco and uphold the measure's intent of driving homeless alcoholics into treatment by stopping the supply of the inexpensive alcohol.

"This stuff . . . is what they're turning to when they can't get the other wines," said Lamont Lawson, Gaithersburg's advocate for the homeless who works the streets each day to persuade alcoholics to seek treatment as part of a city-sponsored program. So far, about 60 substance abusers have gone through the city's program, and Lawson estimates that about half of them were homeless.

Last spring, Lawson encouraged Mayor W. Edward Bohrer Jr. and the City Council to approve the controversial one-year voluntary ban.

While the intent was to prohibit the sales of cheap wines -- the kind with high alcohol levels and $2 a bottle retail price, city officials were compelled to guide the store owners by coming up with a list of banned beverages.

The majority of Gaithersburg's privately owned beer and wine shops voluntarily agreed to halt sales of Thunderbird, Night Train, Wild Irish Rose and MD 20/20. All of those wines have an alcohol content of about 17 to 19 percent, up to 8 percent higher than most nonfortified wines. The county, which operates two liquor stores in Gaithersburg and controls distribution of beer and wine sold by privately owned stores, halted sales as well. The county's support, integral to the ban's success, came even though the director of the Department of Liquor Control, Jerome I. Baylin, opposed it.

"Prohibition didn't work," Baylin said. "People who want to drink will find a way."

In June, store owners said, they began hearing customer requests and industry interest in bringing the Canandaigua Wine Co. brand, Cisco, to the county. Cisco, the strongest of any of the banned wines and manufactured by the same company that produces Wild Irish Rose, has an alcohol level of 20 percent.

Bashar Haddad, owner of Plaza Wine and Beer in Gaithersburg, said he has complied with the ban, but will not stop selling Cisco, because "I've lost enough business from people -- not the homeless -- but working people. We've got to put our foot down."

Haddad said he first learned he could special order the wine from the county when a distributor told him in August it had become available.

Hong An, owner of Villa Beer and Wine, started selling Cisco this summer, but dropped it at the city's request. "I don't think it will work, but I'm trying to sacrifice to help these homeless people," he said.

"It's not just those items I am losing business for," he said. "Postmen and military people buy those wines along with their beer. They go somewhere else now."

Cisco is not sold in county stores.

Despite others' doubts, Lawson said the ban can be effective if Cisco is eliminated from city stores. He said four "street alcoholics" who have begun treatment since the ban, told him they began drinking Cisco when sales of the other wines ended.