CAMBRIDGE, Mass. (AP) – Harvard undergraduates are in a lather over a party where students donned bathing suits and danced in a sea of foamy bubbles, only to wake up the next morning with painful rashes.

Seven or eight students who attended the annual “Mather Lather” party at the Mather House residence hall were later treated for skin rashes at Harvard’s infirmary, according to Harvard spokesman Robert Mitchell.

The party, which drew an estimated 600 students last Saturday night, features a foam-making machine that fills the dance floor with suds. The foam apparently contains a chemical additive that keeps revelers from slipping, but can cause rashes if it isn’t properly mixed or washed off soon after exposure.

Harvard freshman Andrew Trombly said he developed rashes on his arms and legs.

“I knew people who had it all over their body and couldn’t get out of bed in the morning,” he said. “Twenty years from now, it will be funny. At the time, it was kind of painful.”

At www.thefacebook.com, more than 20 students who attended the party joined an online forum called, “I Got a Nasty Rash, but Mather Lather Was Fun.”

“This is HELL,” wrote Harvard freshman Jaime Renee Smith. “I am going to scratch myself until I bleed to death if this continues another day.”

Walker Stanovsky, a student who helped organize the party, told The Harvard Crimson student newspaper that the foam was supplied by Crawford International Theatrical Corp., a party supply company based in Lynwood, Wash.

Stephany Crawford, the company’s vice president, said she has no record of selling the party foam to Mather House.

“When it’s mixed correctly, it’s irritation-free,” she said. “If they don’t mix it with water, it’s pretty strong… It’s still a fantastic product.”