They were taking part in the hospital's monthly "Strength Through Laughter" therapy. It is one of several types of laughter or humor therapy being offered by medical facilities around the country for patients diagnosed with cancer or other chronic diseases.
The programs feature joke sessions, clown appearances and funny movies.
While the verdict is out on whether laughter plays a role in healing, the American Cancer Society and other medical experts say it reduces stress and promotes relaxation by lowering blood pressure, improves breathing and increases muscle function.
On a recent day before Halloween, many of the two dozen patients at Montefiore arrived in costume to "spook cancer."
"The session makes you feel better," said Luz Rodriguez, 57, a breast cancer patient now in remission, who came disguised as a security officer. "I feel healthy when I laugh."
The laughs generated a warmth among the group that was palpable, particularly when Rodriguez changed into an angel costume and went around offering a red rose and a hug or kiss to each of the participants.
Their facilitator, senior oncology social worker Gloria Nelson, started the session five years ago to help cancer patients focus on living, instead of dying.
"They have such amazing strength, but it's a constant challenge, the fear of it coming back, how to go on living knowing you have cancer," said Nelson, who came dressed as the mother of the bride. "Every time they laugh, it's like kicking cancer out the door. You're taking control, you're saying it's not controlling me."
The most famous case of laughter's therapeutic effects on the body was described by Norman Cousins, editor of the Saturday Review, in his 1979 book, "Anatomy of an Illness." He claimed that a combination of laughter and vitamins cured him of a potentially fatal illness.
"I made the joyous discovery that 10 minutes of genuine belly laughter had an anesthetic effect," he wrote.
Still, laughter therapy is not for everyone. Some cancer patients are so overwhelmed with their diagnosis that they are unable to participate. Medical experts stress that laughter and other complementary therapies like acupuncture, massage and meditation are not substitutes for traditional medical treatment but can be used to help relieve the anxiety brought on by the disease.
At the Cancer Treatment Centers of America in Zion, Ill., patients experience another form of laughter therapy that bypasses jokes. In this version, patients practice laughter sounds like "he-he," "ha-ha," and "ho-ho," greet each other with laughter instead of words and engage in games like a pretend snowball fight until laughter overtakes them.
The staff at the center first tried it in 2004. They felt "weird and silly" but when they tried it out with patients the next day, the laughter soon because contagious, said Katherine Puckett, a licensed clinical social worker and a mind-body medicine expert.
The therapy has since been integrated into the culture of the hospital, and is also offered at the center's facilities in Philadelphia, Tulsa and Seattle.