It is said to represent the composer’s love letter to his new bride. And, like love, the Adagietto transports those who receive it — its atmospheric notes offering release from the grim foreboding and frenetic outbursts of the earlier movements of Gustav Mahler’s Fifth Symphony.

But worldly concerns have a way of intruding: an iPhone light, a candy wrapper, one too many trips to the restroom.

The rustling of a gum wrapper at a performance of the symphony last week in the Swedish city of Malmo brought a section of the audience back down to earth — and several concertgoers to blows. Mahler’s late romantic epic became the occasion for an epic clash over candy.

As Andris Nelsons, an eminent Latvian conductor, coaxed the quiet notes from the string section of the Leipzig Gewandhaus Orchestra, a woman in the balcony rustled a bag of gum, the Sydsvenskan newspaper reported. A young man sitting next to her glared a few times and then lost his patience. He snatched the bag from her and threw it onto the floor.

Witnesses told the daily newspaper published in southern Sweden that the woman sat stoically through the rest of the Adagietto, which typically lasts about 10 minutes (“very slow,” Mahler instructed in the score), and the vigorous and triumphant finale. The symphony, composed in 1901 and 1902, has been described as a “large-scale journey,” similar to climbing Mount Everest. Leonard Bernstein conducted the Adagietto at the funeral for Robert F. Kennedy in 1968.

But as the concert hall vibrated with the final, resounding notes, and as applause rang out, she exacted her revenge.

The gum-rustler turned to her neighbor and uttered something, eyewitnesses told the newspaper, and then proceeded to smack him in the face, knocking off his glasses. The woman’s male companion then grabbed the man by the shirt and began to punch him, as the seizer of the gum sought to defend himself.

“It was very unpleasant actually. I’ve never seen anything like it,” said Olof Jonsson, who was sitting in the row behind the brawling patrons. He described the salvo from the woman and her ally as a “violent attack.” At one point, as the tension seemed to ease, the woman’s companion walked toward the younger man as if to converse with him, but then punched him in the stomach.

Other patrons intervened, establishing a cease-fire.

After news of the fracas appeared in Sydsvenskan, the concert venue, Malmo Live, publicized a list of reminders about etiquette, according to the Local Sweden news site. The announcement took a genial tone. While it is “wonderful to sit at a hockey or football match and drink a beer or coffee and eat little snacks,” it cautioned, this behavior doesn’t suit “a concert hall with world-class acoustics.”

“We seized the opportunity and felt that it was a good situation to write something up about etiquette and correct behavior,” Anna-Maria Havskogen, a spokeswoman for the venue, told the news site. She said the venue had no plans to play host to other high-risk concerts.

Except, possibly, Verdi’s “Requiem” next month. “Extremely powerful, will awaken strong feelings,” she said.