Market Scene : In a Green Bottle, a National Symbol : The murky potion is called Unicum. After war, communism and exile, the family that distills it is back in business, and all Hungary is toasting their health.

It smells like medicinal herbs, comes in a round green bottle emblazoned with a red cross and is said to cure everything from hangovers to the malaise that afflicts deal-making Hungarian businessmen after too hearty a lunch of chicken paprikash.

It is Unicum, the 84-proof liqueur so hallowed that the Roman Catholic archbishop of Hungary keeps the secret recipe locked up in his basement safe.

Today, exactly two centuries after the Zwack family first concocted the aromatic alcoholic product that Hungarians embrace as their national drink, Unicum has evolved into a potent symbol of the changes that have swept this Eastern European nation.

Encapsulated within its murky, greenish depths are all the romance and tragedy of Hungary’s history since 1790: revolutions and midnight border crossings to freedom, castles lost and, finally, family legacies regained.

It is the last that most warms the heart of Peter Zwack, a 55-ish polyglot who has returned to his native Hungary to run the family business, which the Communists seized and nationalized in 1948.

Never mind that after 42 years in exile the surviving scion and his partners had to pay $1 million for the privilege. Unicum and Zwack are back in business, selling 4 million bottles last year (in a country with 10.5 million people) and posting at least 10% profits on sales of $20 million.

“We’re a big success story,” says Zwack, who claims to have made back his entire investment in the first year. “It’s no longer a business story but a political one. The government uses us as an example to bring in foreign capital.”

Slender, with the absent-minded charm of aristocrats everywhere, Zwack is a familiar fixture in all the power haunts of Budapest, from Parliament to the Hilton. He boasts equally good ties with the newly elected government and the hordes of businessmen stampeding into Budapest in search of investments.

“The phone rings from 6 a.m. till midnight,” Zwack says. “I had to hire a full-time secretary to answer calls from people, many of them U.S. companies, who come to me for advice.”

Zwack sees himself as a sort of “good-will ambassador to the West.” But he has the same advice for all callers:

“I tell them you have to be very patient.”

Patience is an art the Zwacks honed in their years abroad, after they lost the ancestral business that had made them one of the wealthiest and best-known families in Hungary.

The saga begins in 1790, when Peter Zwack’s great-great-somebody-or-other first distilled Unicum from 40 different roots and herbs. By 1840, the Zwack firm was making 220 liqueurs and fine fruit brandies--for which Hungary is also famous.

Unicum and the Zwacks weathered the Austro-Hungarian Empire and two world wars, amassing a fortune and doing their bit for the Allied cause under the nose of the Nazis.

When the Germans shot down Allied planes headed over Hungary to bomb the rich Romanian oil fields of Ploesti, Zwack’s father would hide the downed pilots in the family castle, near Szeged in southern Hungary.

Toward the war’s end, the Zwack factory was bombed, as were the bridges that spanned the Danube River, connecting Buda with Pest. So the Zwacks supplied wooden barrels that once held spirits to help build pontoon bridges across the river.

But the family smelled trouble in 1948, and as the Communists consolidated their power, the Zwacks fled, with patriarch Janos Zwack, Peter’s father, hiding in an upturned oil barrel on a Russian truck whose drivers he had bribed to take him over the border to Austria. In his back pocket he carried the secret recipe for Unicum.

Young Peter walked through Yugoslavia, arriving in Trieste on New Year’s Day in 1948. The family reunited in Milan, then migrated to New York, where they hid away one-quarter of the Unicum recipe in safety-deposit boxes in each of four banks.

The Hungarian Communists seized the Unicum plant and continued producing the liqueur domestically. But without the exact formula, the Communists could turn out only a pale imitation, and sales dwindled, Zwack recounts with undisguised pleasure.

In New York, the Zwacks had to adjust to a less genteel life style. At a Lexington Avenue hotel, the unsuspecting Janos Zwack, accustomed to silk shirts and servants, left his shoes outside the door to be shined one night, only to have them disappear.

Peter, who spoke five languages, went to work as a vacuum cleaner salesmen in Queens but gave it up when, asked for a demonstration by a prospective client, he couldn’t get the contraption to work.

Eventually, Zwack worked his way up to Connecticut sales manager for a national distilling firm, married a WASP and had five children.

“I was not one who was wallowing in homesickness,” Zwack recalls. “I had absolutely no intention to come back to Hungary.”

Those sentiments were echoed by the Hungarian Communists, against whom the Zwacks filed suit after the government continued producing Unicum under the Zwack name.

After years, the Zwacks won, and the family was paid royalties out of Hungarian government assets that had been frozen after the war.

But although Zwack called his family and the Communists “the deadliest of deadly enemies,” fate and glasnost were working to bring them back together.

In 1970, Peter Zwack moved to Milan to run the family’s Italian liqueur operations. He also divorced, married an Englishwoman named Anne Marshall and produced two more children, a son, now 15, and a daughter, 13.

Zwack still called the Communists “gangsters” but when they invited him home in 1988, he agreed, gambling rightly that Hungary was about to usher in a new era. Last year, during President Bush’s visit, Zwack signed a million-dollar joint venture with the Hungarian state distilling firm to produce Unicum.

Zwack and the German distilling firm Unterberg each contributed $500,000 for a share of 25% apiece. The state distillery got 46%--paying for most of it with equipment from Zwack’s original factory. A Hungarian bank and an export firm in Budapest each contributed 2%.

“We bought back what was stolen from us,” Zwack says somewhat heatedly over a lunch of salad and espresso at a posh Western-style hotel where the waiters all know him by name.

“Perhaps you’d better not say that,” urges his wife, who is a bit more of a diplomat.

Monetary details aside, the Hungarians welcomed back the original Unicum like a long-lost cultural icon.

In some ways, it had never left. Zwack says that during the hard Stalinist years, the famous Unicum poster--showing an ugly, bearded man, adrift at sea, who grins demoniacally when a bottle of Unicum bobs by to save him--became a sort of symbol of resistance.

“In the villages, it was a poster of hope, a sort of samizdat (underground letter) that said, ‘We won’t go under,’ ” Zwack explains.

The brand name also played a modest role in the Hungarian Revolution of 1956, when freedom fighters filled empty Unicum bottles with gasoline, added wicks, lit them and lobbed them at Russian tanks.

And last summer, when then-Communist Party boss Karoly Grosz was foundering under the accelerating pace of reforms, a well-respected economic weekly replaced the man in the poster with a caricature of Grosz alongside the caption “Not even Unicum will save Grosz now.”

Today, Zwack employs 70 people in a Budapest factory and has installed new equipment. Sales of the original Unicum continue to mount, with Zwack profiting from the growing number of tourists who want to lug back authentic Hungarian souvenirs.

“The problem we had in Italy was one of identity,” Zwack says. “It’s an enormous plus to be back in your homeland.”

Zwack, who also holds U.S. citizenship, says he distributes 10,000 bottles a year in the United States and plans a marketing campaign this fall to try to turn Unicum into an “in drink.”

The liqueur already has a small but loyal following, says Peter Matt, president of Winebow Inc. in New York, the nation’s only importer of Unicum.

“Your customers are people who are sophisticated, who have some understanding of the product. It’s like fine wines,” Matt says of the spicy liqueur, which fetches $22 for a 24-ounce bottle.

But Zwack himself admits that Unicum--a digestive with many of the same herbs as Campari, a kind of bitters--is an acquired taste.

“Many Americans I know, the first time they try it, it’s a disaster. The second time, they’re hooked.”

When not running his own firm, Zwack is busy as chairman of the Foundation for Development of Small and Middle Companies, which doles out loans to fledgling firms and teaches Western business skills in former Soviet barracks vacated by departing troops.

“I’m not the ugly capitalist, but the socially thinking free-enterpriser,” says Zwack, who without any embarrassment calls himself “one of the most popular guys in Hungary.”

He also scotches rumors that he may play a role in the new government, dominated by a right-of-center party called the Hungarian National Forum; he says he has no aspirations for office “at this time.”

For now, Zwack and his wife keep a home in Milan and an apartment in Budapest’s hilly castle district overlooking the Danube, just two doors down from the former Zwack family home--which now houses the Turkish Embassy.

But despite his confidence in the new government, Zwack says he plans to keep open his Italian operations, which produce 1 million bottles annually.

The man who fled Hungary on foot 42 years ago leans forward to explain:

“As a safety valve.”