So what if it was midnight. Antoinette Brent needed antibiotics for her sick baby, the visiting nephews of Artavius Clark had a sudden urge for Froot Loops, and Percy Brown, a handsome young tourist from Memphis, needed a personal item "they apparently keep behind the counter."

Even though it was the middle of the night, the customers had to wait in line. They stood patiently at first, then paced around a bit inside Washington's ever-busy and only all-night drug store --- Peoples at 14th Street and Thomas Circle in the heart of downtown's disco-skinflick-good-time-Charley combat zone.

Outside, a lanky young man took long drags on a cigarette and walked by asking, "Anybody seen Cathy or Snow?"

"Nope," answered 9-year-old Michael Husin Jr., as his 7-year-old sister, Fadi, poked her head under his arm and shook her head. The two stood just outside the store on the sidewalk where their father, michael Sr., a street vendor, hawks incense, tapes and T-shirts.

"Cathy and Snow are friends of ours," Fadi explained before skipping back down the street, dodging among the pimps and prostitutes she and her brother call pals.

For years, prostitutes have walked this strip of 14th Street. On humid summer nights, scantily clad women line the curbs in clusters of four and five and peer into double-parked cars or dodge between moving ones that clog the area.

But it is here also that legitimate business is transacted. Customers from all over the city flow in and out of Peoples: parents with sick children, teen-agers with the munchies and chainsmokers out to assuage a nicotine fit.

They come, spurred by late night urgencies and undaunted by the flitzy night denizens, the screaming police sirens and light clouds of marijuana smoke mixed with the city's steamy summer haze.

Once inside Peoples' glass doors, the customer seems worlds away from the street. Flourescent blubs startle the eye and cast a bright sterile light across rows of toothpaste and tissues, corn chips and Kool-Aid, batteries and Band-Aids.

Recently, 10 people waited at the pharmacy counter just before midnight as lines six and seven deep formed at two cash registers.

"I didn't expect this kind of line at this hour," said Percy Brown, who had one more week in town before returning to Memphis.

Gyda Hinton of Silver Spring said she ran out of formula for her infant son and purchased two cans of Enfamil.

"I'm here for a fan. It's on sale," said Olga Bailey, who had come across twon from her stuffy apartment in the Montana Terrace public housing project in Northeast Washington. Her short hair mattted under a visor cap, Bailey said she was shopping late because "we got hot. It was cool at first you know."

Then there are those whose needs seemed less urgent. A rumpled old man flipped through magazines. A middle-aged woman browsed through shelves of greeting cards. Two couples chatted in front of the soft-drink cooler.

Some late night customer live nearby. Others, like Vivian and Fay Pon, who came by for a carton of milk, are guests at downtown hotels.

Still others come from afar, such as Olga Bailey and Chantal Taquay, a resident of Geogetown seeking emergency relief for a friend with several abscessed teeth. "There ought to be a lot of all-night stores," Taquay said.

Peoples has two other all-night stores in the area, in Arlington and Langley Park. The only other major all-night drug store and pharmacy is at a Drugfair outlet on Glebe Road in Arlington. Dart Drug has all-night stores in Maryland and Virginia, but pharmacies at those stores close at either 9 p.m. or 11 p.m.

Despite the nighttime crowds, "If we had to exist from the business we do from midnight to 6 a.m.," Peoples Vice President Joseph Pollard said, "we'd probably be losing money."

The all-night drug store is a public service, not an efficiency measure, he said. "We're in a semi-medical business and have a public trust," he said.

Crime is no problem inside the store, according to D.C. police and store management. Manager Frank Tracey said the Thomas Circle store was last robbed 2 1/2 years ago by an unarmed teen-ager who got away with two $20 bills.Security guards, described by other employes as firm but fair, keep a close watch on troublemakers from the street.

"It's a pretty safe store on the inside," D.C. Police Lt. William B. Riley said.

A swing through the store's smudgy lass doors leads back onto the street where police are waging a campaign to cut down prostitution and late night traffic congestion. More uniformed and undercover officers have been assigned to patrol the streets. Police also have blocked off parts of the roadway in front of the drug store after 10:30 p.m. to ease the congestion for customers. "We're trying to keep down the traffice that keeps circling the block, that keeps slowing down and waving and cajoling," Riley said.

Bright red lights from the Den go-go club pulsate from across the street and onto the childhood games played by Michael and Fadi Husin on the sidewalk outside Peoples.

Their street vendor father, a Palestinian who emigrated here 15 years ago, keeps them with him on the strip afternoons and sometimes until late at night. He set up shop seven years ago to catch the Peoples trade.

He and his two children know the store clerks, guards and managers. Sometimes they trade inside information on possible troublemakers, Husin said.

"Every day somebody snatch something. I look up and it's gone," Husin said. He said he alerts the store because "if you steal from me, you steal from them."

Husin and his children said they know many of the people who work outside the store as well, including some of the prostitutes and their pimps who patrol the street.

"I know them for a long time," said kHusin, a tiny, middle-aged man with eyes that squint even in the dark. "They don't bother me."