Pearl Bailey, the dynamic and irrepressible singer, actress and comedian whose throaty-voiced performance in "Hello Dolly!" was one of the monuments of the musical stage, died yesterday in Philadelphia. She was 72.

A spokeswoman for Thomas Jefferson Hospital there said Bailey was brought to the emergency room unconscious at 5:45 p.m., apparently after collapsing at a downtown hotel. Cardiopulmonary resuscitation was performed, but she died about half an hour later.

The cause of death was not immediately known, and an autopsy will be performed, according to the spokeswoman, Kellyann McDonnell. Bailey, a star of stage and screen, had suffered from a heart ailment for many years.

A performer whose warm-hearted spontaneity and infectious enthusiasm captivated audiences around the world, Bailey was a woman of great drive and determination. She served the nation as a diplomat, wrote several books and received a bachelor's degree from Georgetown University at the age of 67.

Reared in Washington, she sang as a teenager on U Street NW, when it was known as a black Broadway. She also lived here later in life, during the seven years that she juggled her career and the studies that led to her degree.

The degree was in theology, but Bailey was recognized as the originator and leading proponent of what was described as her own particular, all-embracing philosophy of love and universal harmony, which she expounded to audiences around the world.

On stage, in theaters and nightclubs, Bailey, affectionately known to fans and friends as Pearlie Mae, was raffish and brassy, sometimes delivering her lyrics in a style she called preaching, or sometimes talking them in a deep-throated rumble akin to a growl.

Though she often appeared particularly relaxed, she could also be stirring. On July 4, 1989, she brought a huge audience assembled on the grounds of the U.S. Capitol to its feet with her rendition of "The Battle Hymn of the Republic."

Her road to fame was a long one, taking her from the honky-tonk world of coal town cafes in Depression-era Pennsylvania to New York, Hollywood and frequent guest appearances at the White House.

In addition to receiving the informal portfolio of "ambassador of love" from President Nixon, Bailey served later Republican presidents as a member of the U.S. mission to the United Nations. Asked once about her U.N. work, she said, "there should be less hatred . . . . There should be more love, more reasoning and definitely less paper."

She received the Medal of Freedom from President Reagan in 1988.

Bailey and her husband of almost 38 years, musician Louis Bellson, had been living most recently in Lake Havasu City, Ariz. They had two adopted children. Recently, she had undergone surgery at Pennsylvania Hospital in Philadelphia to replace an arthritic left knee with an artificial joint. She had remained in the city after leaving the hospital to visit relatives while she underwent therapy as an outpatient.

Bailey was born in Newport News, Va., on March 29, 1918. Her father, the Rev. Joseph James Bailey, was a Pentecostal preacher whose exuberant, revival-style services influenced her. By the age of 3, she was singing and dancing in his church.

"From him," she once told an interviewer, "I got the wisdom, the philosophizing, the soul."

Bailey traced her acting skill to her mother, Ella Mae Bailey. "She could say more with a flick of a wrist . . . than any words," she once said.

Bailey moved here with her family when she was a preschooler. Her parents divorced early in her life, and she lived as a teenager in Philadelphia, where she attended high school.

She had two sisters and a brother. The brother, Willie, known as Bill, became a professional dancer. By one account of her early career, Bailey was 15 when she won first prize in an amateur contest at the Pearl theater in Philadelphia, where her brother was appearing.

In an article in The Washington Post Magazine two years ago, Bailey told of being given a chance, when she was 15 1/2, to sing at a U Street club in the District. The salary was $12 a week.

"I had never sung before," she said. "That was my first job." Later, she said, she got to work "at some of those fancy-pants places" along U Street that were "filled with doctors and lawyers."

Other accounts tell of an amateur contest at Harlem's famed Apollo Theater, an appearance as a dancer with Noble Sissle's band and work as a chorus girl in Philadelphia nightclubs. After her tour of Pennsylvania's coal district, she sang in clubs here and in Baltimore, as a solo act and with several musical groups.

After the outbreak of World War II, she toured with USO troupes and made her New York nightclub debut as a soloist at the Village Vanguard, reportedly where a suggestion that she relax and show her true self on stage led to the development of her singular style.

Bailey's career progressed rapidly. After a stint with Cab Calloway, she made her Broadway debut in March 1946 in "St. Louis Woman," a musical with an all-black cast.

"Pearl Bailey pulls the show up by its shoestrings every time she makes an entrance," a critic wrote. She won the 1946 Donaldson Award as Broadway's best newcomer.

The next year she was in her first movie, "Variety Girl," and after making a second, "Isn't It Romantic," she was back on Broadway for two shows. For years thereafter, she brought her solo act to theaters and clubs across the country while continuing to make stage and film appearances.

Bedecked in rhinestones, she enlivened 20th Century-Fox's "Carmen Jones," and her warmth and earthiness characterized her role as Maria the cookshop woman in MGM's "Porgy and Bess."

One of her great triumphs came in 1967, when she was chosen to head an all-black cast of a new production of the long-running Broadway hit, "Hello Dolly!"

When the show opened at the National Theatre here, President Johnson and his wife, Lady Bird, joined the cast on stage for curtain calls.

It opened on Broadway on Nov. 12, 1967, enthralling audiences and winning critics' most lavish praise.

Bailey described the show, which won her a Tony Award, as a "fantastic emotional experience" that allowed her to "sing, dance, say intelligent words on stage, love and be loved and deliver what God gave me -- and I'm dressed up besides."