In cystic fibrosis, a defective gene lets mucus collect in the lungs, making them vulnerable to infection—which causes lung damage. The primary treatment is impressively low-tech: whacking on the patient's chest and back to loosen mucus. Two studies published this week in the New England Journal of Medicine report success with another low-tech treatment: saltwater.

Patients in both trials inhaled saline through a nebulizer for 15 minutes at a time. The long-term trial, in Australia, compared the stronger salty solution with a very mild saline, used as a control. In another trial, carried out at the University of North Carolina–Chapel Hill, patients were given either the saline alone or the saline with a diuretic.

In both studies, using the salty solution helped patients breathe better and moved the mucus out of their lungs faster. Adding the diuretic did not help; in fact, it made the saline less effective. Patients inhaled the saline in addition to any other drugs they were taking for cystic fibrosis. "It tastes like you just swallowed a bit of ocean water," says Jenny Bailey, 22, who was diagnosed with cystic fibrosis as a baby and took part in the study at the University of North Carolina. She thinks the saline, which she uses every day, helps keep her out of the hospital.

In the Australian study, the researchers found that patients who had the full salty treatment, instead of a treatment with very mildly salty water, were much less likely to be hospitalized or need intravenous antibiotics.

The treatment was suggested by years of laboratory research into how cystic fibrosis works; researchers concluded that patients don't have enough salt and water on the surfaces of their airways. As a result, the mucus that collects is too dry for patients to cough up. Patients' own stories inspired the work, too, says pulmonologist Scott Donaldson, who led the study at the University of North Carolina. "In Australia, that was a common anecdote patients would give—when they were out at the beach surfing, they felt more clear in their chest, less congested."

The treatment isn't a good idea for patients who have asthma, because it can provoke wheezing. Bailey says the saline made her cough a lot at first.

In the 1950s, the median life expectancy for a baby born with cystic fibrosis was 2 years; now it is 34, Donaldson says. The youngest patients in the trials reported last week were 6 years old. Donaldson says he hopes to be able to test the treatment on infants soon.

"This is really the first therapy that addresses the underlying problem in cystic fibrosis—that is, dehydration of airway secretions," he says. "Potentially we can get in early on the course of the disease and essentially correct it." Letting babies breathe saline, he says, could prevent a lot of the infections and lung damage that normally build up in children with cystic fibrosis.

Learn about cystic fibrosis from the Cystic Fibrosis Foundation: http://www.cff.org/home/

Information about cystic fibrosis from the National Library of Medicine: http://www.nlm.nih.gov/medlineplus/ency/article/000107.htm