Dear Doctor: I keep hearing about something called halotherapy, or salt therapy. Can it really help people who have respiratory problems and inflammation? I’ve heard that it’s good for arthritis and for regulating blood pressure, too.

Dear Reader: Halotherapy is a centuries-old spa treatment that’s definitely having a moment. Although the specifics of the practice are as varied as the establishments that offer it, it basically involves inhaling salt particles that have been rendered minute enough to be breathable.

Enthusiasts promote halotherapy as an alternative treatment with, as you point out, a wide and diverse array of purported benefits. These range from help with respiratory issues, infection and a variety of skin conditions, to relief from anxiety, depression, inflammation and immunity problems. Skeptics, including some in the medical community, consider halotherapy to be a pseudoscience.

The medicinal use of salt dates back at least to the ancient Egyptians, where it was cited in papyrus manuscripts as an effective antibiotic, skin treatment, birth aid and laxative. These practices then found their way to the ancient Greeks and Romans and the early Arab world, and they were later adopted in Europe during the Middle Ages, the Renaissance and beyond.

The modern practice of halotherapy arises from observations made by physicians living near the salt mines of Eastern Europe and Russia at the start of the 19th century. They noticed that unlike laborers who mined ore or coal, work that took a steep physical toll, salt miners had no respiratory problems and remained in relatively good health. This was attributed to the microparticles of salt created in the course of mining operations, which the miners breathed throughout their working hours and also had on their skin.

This discovery led to the founding of a health resort in the 1840s -- and later to numerous spas and resorts -- where patrons spent time inside salt caves, breathing and exercising. Today, spas and other facilities build their own salt caves using tons of rock salt. A grinding machine is used to reduce salt to microparticles, which are circulated throughout the space for patrons to breathe during timed sessions.

Health claims regarding halotherapy are abundant -- and largely anecdotal. A handful of studies published in the last decade have linked halotherapy to varying degrees of improvement among individuals with chronic respiratory issues such as asthma and COPD. However, questions about methodologies, including randomization and patient selection, have called some of those conclusions into question. At this time, rigorous scientific studies into the practice remain scarce.

When it comes to how halotherapy works in cases of respiratory illness, no one really knows. Proponents point to the antibacterial and antifungal properties of salt. Some believe the salt-laden air helps to thin out mucus, which allows for improved function of the body’s natural immune processes and cleansing mechanisms.

If you do give halotherapy a try, make sure the facility provides adequate ventilation. One study found increased levels of bioaerosols, which are minute biological airborne particles, in underground salt caves used by groups for therapy and exercise. And since salt is a diuretic, we think it’s wise to replenish fluids and use moisturizing eye drops when you’re done.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I’ve got a blocked tear duct that I’m told requires surgery. My eye weeps, but it isn't painful. However, it has become infected once. What can you tell me about this condition, and what are my treatment options?

Dear Reader: We’re all aware of the tears we produce in abundance -- such as when we cry in times of emotion, or when our eyes fill with reflex tears in response to an irritant. However, our eyes are continuously producing a third type of tear, known as basal tears.

As with most tears, basal tears come from the lacrimal glands, which are located above the outer third of each eye. Although basal tears aren’t nearly as abundant as emotional or reflex tears -- we secrete less than a gram of them per day -- they are essential to the health and optimal functioning of the eye. With each blink, the eyelid spreads the basal tears, which coat the eye with a complex film of water mixed with mucus, fatty oils and more than a thousand different proteins. Basal tears lubricate and nourish the surface of the eye, most specifically the cornea. This is the clear, colorless dome that covers the front of the eye and forms its outermost layer. Basal tears also play an important role in focusing light.

After basal tears complete their journey down and across the eye, they drain into structures known as puncta. These are tiny openings in the corners of the upper and lower eyelid. The spent basal tears, along with whatever debris they may have cleared from the surface of the eye, then move through a series of ducts and canals that empty into the nose.

When any part of the tear drainage system becomes blocked, the constant flow of basal tears has nowhere to go. This causes them to back up onto the surface of the eye, which becomes watery, red and irritated. Other symptoms of a blocked tear duct can include swelling in the inner corner of the eyelid, blurred vision, mucous discharge and crusty lids or eyelashes. As you have already experienced, a blocked tear duct can also increase the risk of infection.

Blocked tear ducts in adults are most commonly caused by eye infections, swelling, injury to the nose or eye, polyps or a tumor. Age-related changes to the structures of the eye, such as narrowing of the punctal openings, can also play a role. Diagnosis entails a complete eye exam, as well as specific tests to assess the degree of blockage.

Treatment is based on the results of those tests. Infection is typically treated with a course of antibiotics. The blockage itself may respond to a special massage technique, or may require one of several different types of surgical intervention. These can include the use of a series of instruments to clear the blockage, opening a narrowed duct with a balloon catheter, implanting a temporary stent into the duct, or creating a new route for tears to drain from the eyes and through the nose.

As with any medical procedure, be sure to understand all of the available treatment options, and discuss them with your doctor.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Our family loves the summer barbecue season, but the “take the fun out of everything” lobby keeps saying this can increase our risk of cancer. Just how unhealthy is grilled meat? Can we do anything to make it safer?

Dear Reader: The potential health threat of grilled meat is one of those cyclic news stories that pops up each spring as reliably as the first crocuses. The issue has its roots in decades of science, but the subsequent writing about the potential risks has ranged from measured and helpful to off-the-charts alarmist. To sort through the noise, let’s start with some basics.

When we cook meat over high heat, or to high temperatures, a number of chemical compounds, a few of them potentially dangerous, are formed. The grilling of beef, poultry, pork, fish and other muscle meats creates heterocyclic amines, or HCAs. These are formed not only in grilling, but during other high-heat cooking, such as broiling, pan frying and deep frying. When meat juices ignite on the hot coals beneath the grill, or when they come into contact with any surface hot enough to evaporate liquid and create smoke, that smoke contains chemical compounds called polycyclic aromatic hydrocarbons, or PAHs. When the smoke comes into contact with the meat -- and whatever else is on the grill -- it leaves behind potentially dangerous compounds. Lab experiments have shown that HCAs and PAHs have the potential to cause changes to DNA, which means that they may increase the risk of cancer.

So far this all sounds pretty grim, so it’s helpful to put things into context. In lab experiments, most of them conducted in test tubes and in animals, researchers use doses of HCAs and PAHs that are extremely high, the equivalent of thousands of times the exposure of a person eating a typical diet. By comparison, the levels of HCAs and PAHs generated by home cooking and grilling methods are quite low. However, ongoing population studies continue to find a link between grilling and a slight increase in cancer risk. The takeaway here, as with so many pleasures in life, is moderation.

When it comes to grilling, a few simple steps can make your meal safer. First, grill meat separately from other foods to limit exposure to PAHs, the compounds contained in rising meat smoke. Vegetables, fruit, bread and pizzas, all popular grilling options, should be cooked at a different time from the meat, or at the very least on their own side of the grill. When it comes to meat, it’s wise to avoid high cooking temperatures and prolonged cooking times. Turning meat frequently while it’s on the grill helps keep charred areas from forming. Be sure to remove any charred portions before serving and eating.

A final note -- studies have shown that acidic marinades that contain no sugar (but spices are fine) can significantly reduce the formation of PAHs. A marinade of lemon juice reduced the generation of PAHs by 70%, while lemon juice mixed with oil reduced PAHs by 57%. We hope this helps, and that you have an enjoyable and healthful grilling season.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)