The first thing you notice when you enter the Salt Cave is the floor: It crunches.

Your bare feet slide gingerly across the pebble-like floor covered with 4,000 pounds of Himalayan salt crystals. The walls around you are lined with pink and orange-hued bricks of salt. As you slide into one of the zero-gravity chairs, you hear the sound of crashing waves streaming from overhead speakers. As you relax and your breathing slows and deepens, you inhale air pumped with pharmaceutical-grade salt. After a few minutes, you touch your tongue to your lips and taste salt.

This total sensory experience is called salt therapy, a homeopathic remedy meant to help respiratory problems. The age-old alternative therapeutic remedy, sometimes called halotherapy or speleotherapy, is said to alleviate symptoms of asthma, allergies, anxiety and other ailments.

There are no U.S. clinical studies examining the effectiveness of salt therapy, but its adherents swear by it.

Lori Danielson is one of them. Danielson, who suffers from allergies, is a regular at the cave in south Minneapolis.

"I get energy and more oxygen into my body. I've noticed my nasal passages clear up," said the Bloomington resident. "The biggest benefit is I know I can breathe."

Co-owner Scott Wertkin said his Salt Cave — which opened a year ago in a former chiropractor's office — is one of only 30 or 40 businesses nationwide offering this treatment. Other centers have opened in New York, Florida, California and Chicago in recent years.

New life for old practice

Although new here, salt therapy's use in modern history dates back to 19th-century Poland.

In 1843, a physician named Dr. Feliks Boczkowski noticed that workers at a salt mine, unlike other miners, did not have respiratory or lung problems. He attributed their healthy lungs to the air climate inside the salt mine. Salt is known to have anti-bacterial and anti-inflammatory properties. Soon, spas opened in the salt caves and today the therapy is popular in Eastern Europe, Russia and Canada.

Wertkin became interested in salt caves when he and his wife were researching remedies for their son, Jack, now 13, who has asthma. They visited a salt room in Florida and were amazed at the difference it made for their son. They decided to open their own business after learning that Chicago was the closest city with a comparable salt room.

They sought to emulate the look of a real salt mine by transforming the chiropractor's exam room into an otherworldly space.

Wertkin constructed the cave out of 12,000 pounds of rock salt shipped from a mine in Pakistan on the edge of the Himalayas. (The most popular salts used in salt therapy are Himalayan and Dead Sea salts.)

Wertkin compares the salt room's effect on customers' nasal passages to "a dry Neti pot." He said more than 3,000 people have visited the Salt Cave, located in a tiny strip mall next to a yoga studio.

Does it work?

Doctors remain skeptical about the health benefits of inhaling dry salt particles.

"There is no science behind it," said Dr. Scott Davies, a pulmonologist at Hennepin County Medical Center.

Ingesting salt does have therapeutic properties. A 2006 study in the New England Journal of Medicine found that saline therapy was an effective and safe supplemental treatment for patients with cystic fibrosis.

But Dr. Charlene McEvoy, another pulmonologist and head of the Asthma Center at HealthPartners, said there is a difference between sitting in a salt-covered room and ingesting a solution of salt and water directly.

She also cautioned that patients with conditions such as asthma should not replace their medications with salt therapy. "If by doing the salt therapy they couldn't afford their medications, absolutely not. I have data on their inhalers. I know they help. Mortality for asthma has dropped significantly using our current medical treatment," she said.

Davies acknowledged there's a history of "people using [salt] as a homeopathic remedy," and said he knew of no harm that could come from sitting in a room full of salt. Rather than a medical treatment, Davies said, he would put salt therapy in the same category as a spa treatment.

Maybe that's a good comparison.

The last time Valerie Petit, another salt-therapy enthusiast, made a trip to the Salt Cave, she fell asleep. Petit said she goes to the cave mainly to unwind in the beach-like environment. "I don't have any health issues," she said. "I'm just doing it because it feels good."

And even McEvoy said there could be value in asthma patients doing anything that allows them to relax and slow down their breathing.

Cost, perceived benefit

A 45-minute session of salt therapy costs $30. The cave also is used for groups doing yoga, meditation or story times for children. Terri Peterson, a pharmacist, leads a breathing class once a month inside the cave. She said her sinuses open up, an effect that can last for a few days.

Eric Christopher, a member of Peterson's class, said he's been to the cave more than eight times since first reading about salt therapy in an alternative health newspaper. He occasionally will take an antihistamine for his allergies, but he believes the breathing classes in the salt cave have helped. "I woke up having had a restful, deep sleep," he said after a recent visit to the cave.

Christopher isn't deterred by the lack of research on salt therapy.

"I let my own experience be my guide in that," he said.

Allie Shah • 612-673-4488