Eleven-year-old Vaughan Monroe has discovered that kung fu films can be hazardous: They produce bad reactions from his mom. "We'd watch the movies and then go play kung fu in the bathroom, kicking the toilet paper around and stuff. She got mad. She doesn't want us to go," he said. She even took away his karate lessons.

But that hasn't kept Vaughan and most of his friends in his Silver Spring neighborhood from adopting one of suburban Maryland's two Chinese theaters as a weekend second home. With hundreds of kung fu-crazy local youths like Vaughan and a growing Asian population in the metropolitan area, the Cpri China Theater at 8630 Fenton St. in Silver Spring and the Roth's Manor in Rockville have thrived by providing some of the only Chinese-language entertainment available locally.

"I like kung fu; that's why we come every Saturday," said Jean and Ralph Baptiste, 15- and 13-year-old brothers, as they emerged, rubbing tired eyes, from a string of movies at the Capri last Saturday. The Baptistes visit the theater every weekend with an entourage of friends from their Silver Spring neighborhood. "They're better than any other movies," declared Danny Redfern, 14, a member of the contingent, "The American kind, they seem kind of fake. These show more blood."

The older of the two theaters operates out of the Roth's Manor, at Norbeck and Bauer avenues in Rockville. The theater belongs to the mammoth Roth chain which, during the week, offers the standard first-run movie fare.

But after midnight each week night and every weekend afternoon, the Roth's Manor screen is transformed into scenes of whirling knives, flying kicks and the othe exploits of a host of kung fu superstars. Behind the metamorphosis is a cheerful workaholic named Kathy Huang, who began leasing the theater four years ago so she and her friends could see their favorite films.

"I used to work for a film company in Taiwan," said Huang, who came to the Washington area with her husband and three children in 1964. The family now lives in Olney. "But when I came here there was not enough entertainment and no Chinese movies. I think the Chinese should have some kind of entertainment."

Huang decided to fill the gap herself, and soon the crowds became so large, she said, that she decided to buy a theater to show Chinese-language films full time. Two years ago, in October, 1979, Huang took over the 750-seat American Theater in Southwest D.C. Now, with the help of her family and general manager Kilena Loveless, Huang offers fans at both theaters a variety of films from the production houses of Hong Kong and Taiwan. Her taped film announcements are in English and Chinese, and her fresh seame balls, noodle cake, cuttlefish and jerkies fill her concession stand, next to the popcorn and M & Ms.

Similar reasoning motivated Feifei Chan, owner of the Capri, according to her son Steven. "We just started as entertainment for five families because we all liked the movies," said Steven Chan, 23, who manages the Capri along with his wife Amy. Chan added that their idea was not original. About 12 years ago, he said, Chi-ming Woo, owner of the Peking Restaurant at 15th and I streets (in Northwest D.C.), used to show movies at the Circle Theater occasionally, but he has since retired.

The five families, however, decided they wanted entertainment closer to their homes in Virginia, and about seven years ago began to rent the K-B Cinema 7 in Falls Church on weekends. Ultimately, said Chann, the K-B chain offered them the 800-seat Rosslyn theater in the Rosslyn section of Arlington. Fei-fei Chan decided to buy it three years ago. When the Rosslyn did well, she next bought the Capri, which she opened in February this year.

The most recent purchase, however, owed little to the desire for family fun. "It was so we could secure more products and reduce our operating costs," said Steve. Costs are minimized further by employing mostly family members, and by stocking the concession with goodies from their Chinese grocery. "When we started, we didn't know anything," he said, "We just learned right here.

"But," he added, "we're basically nonprofit. All the profit we make from the theater goes to the dinner table."

Audience members are likely to be middle-aged Chinese women as action-hungry teen-agers. "They bring the whole family," said Kathy Huang. And why not, she asks: "It's not just fighting. There's philosophy, history culture." One of her favorite films, "Lion vs. Lion," features a traditional lion dance that is rarely performed in this country.

"In Chinese films the violence is not what's promoted," added her daughter Caroline, a communications major at the University of Maryland. "It's the technique, the style of martial arts. They're definitely bloody, but not, I think, up to the level of what you'd see in a horror movie."

Most members of the audience seem to agree. Yvette Browder, 18, of District Heights, brought her 10-year-old brother to the Huangs' theater. "I don't look at it as violent," she said. "I look at it as controlled. And this is a way to learn about another culture."

Kathy Huang does remember one film she couldn't watch, however. It was about refugees, and the torture scenes drove her -- and some customers -- out of the theater, although she felt obligated to continue showing the film. Steven Chan, however, said he will censor scenes, particularly sexually explicit ones, that the family finds offensive.

Chan wouldn't disclose costs or profits, but he said none of the theaters is "as profitable as people think," because the large movie houses are expensive to operate. Unlike American-made, commercially produced films, which may cost a theater owner $100,000 for a three-week run, the top price for a Chinese film runs about $5,000, however, and this only for a sure box-office draw such as Jacky Chan, hailed as the biggest star since the late Bruce Lee.

Said David Huang, Kathy's husband and a part-time helper, "We charge $4 but we show a triple feature. That's $1.33 per movie. In the summertime a lot of people pay $4 and stay here for 6 hours. It's cheaper than a hotel."

The Huangs choose most of their films from a selection offered by the Shaw Brothers, headed by Sir Run Run Shaw, the D. W. Griffith of Hong Kong films. The Shaw Brothers, probably the largest film production company in Southeast Asia, turn out 52 first-run movies each year -- necessarily, since "it takes a lot of production to keep us in business," said David Huang. The Huangs get about 10 percent of their films from independents. They show two martial-arts movies and a romance or comedy each day. The Chans obtain most of their films from five independent distributors in New York, who get their films from Taiwan and Hong Kong.

The people who rely on the theaters for their weekend entertainment care little about the source of the films. They're just glad the theaters are around.

"Our friends all go to the Chinese movies," said Kyong Yi, 23, as he entered the Capri. "It's kind of our movie."

"It gives us some religious roots," said Yi's friend Byeong-ho Lim. "Like our Buddhism, it reminds us of our traditional (culture). Especially me," said the 22-year-old Korean. "I'm only seven months here and I'm homesick."

Many of the Vietnamese and Koreans in the area cannot understand the Chinese spoken language so they rely on the subtitles in Chinese characters, which they can read. And some, such as Loan Mai, a 17-year-old Vietnamese, practice their English by reading the English subtitles Loan Mai says she doesn't restrict herself to "dopey" romances.

"I don't like love stories," she said. "I do care about all the bleeding. (It's) kind of gross. But I like the fighting-by-hand movies. All the Vietnamese do. Plus," she adds, with a shy smile, "The American movies . . . are kind of about sex a lot. So I don't like it. Also, my mother doesn't like me to watch it."

Despite the informal beginnings of these ventures, both owners now feel that the growth of the area's Asian population, which accounts for about 60 percent of their audiences, practically ensures them of success. "Without the Vietnamese in this area, we would not survive," said David Huang.

Population statistics confirm that assessment. Of the approximate 3.06 million Washington area residents counted in the 1980 census, about 82,147 are of Asian-Pacific ancestry. The American Refugee Committee says that, as of May 21, 710 Indochinese refugees live in this area.

Of course, not all the regular customers are Asian. Some, such as 17-year-old Patrick Brooks, just want to practice their kung fu. "Of course, sometimes I watch the classics," he said, "You know, like 'Clash of the Titans' or Superman.' It takes my mind off the kung fu."