DEAR DR. GOTT: Do you have any suggestions to cure a chronic, choking cough? My sister has tried almost all possible remedies, but nothing seems to work.

DEAR READER: Everyone coughs occasionally for one reason or another. The continuation for several weeks or longer, however, is classified as chronic and occurs when an irritant stimulates nerves in the respiratory tract. While we commonly consider irritants to be pollutants or chemicals emitted into the air, they can result from perfume, room fresheners, foods, spices, fresh flowers and a host of other possibilities.

What bothers one person might not affect another. Then, to make matters worse, the cough may be accompanied by shortness of breath, wheezing (particularly with asthma), a runny or stuffy nose, and less frequently hemoptysis (blood in the sputum). Chronic cough can occur because of postnasal drip, acid reflux, chronic obstructive pulmonary disease (such as chronic bronchitis and emphysema), asthma and in a very small percentage of the population, lung cancer.

Statistics indicate that women are more sensitive to cough reflexes than are men. Is your sister exposed to harmful irritants such as cigarette smoke — either as a smoker herself or through secondhand smoke? Is she on any medication, particularly for heart failure or high blood pressure? If so, she might have her answer. An angiotensin-converting enzyme (ACE) inhibitor cough is present in almost one-fifth of all people on this type of blood-pressure medication. Does she work in a facility that produces irritants, or perhaps a family member does and the offending substances are carried to her home via work clothes?

Your sister should be in the hands of a qualified physician who can sort out the possibilities and make a decision regarding treatment. If she has had the cough for some time now, it will likely remain until a physician can determine the cause. He or she may find it necessary to prescribe an antihistamine, modify the medication she may be taking, draw blood, schedule a chest X-ray or CT scan, or refer her to a pulmonologist (lung specialist). Once the underlying source of the cough is identified and treated, it should disappear, allowing your sister to regain a normal life.

DEAR DR. GOTT: My daughter is a college student majoring in musical theater. She has begun daily saline nasal rinses, where she puts saline up her nose using a special device. She states that the saline comes out of her eyes, nose and mouth. Is there any harm in doing these rinses? She does it to keep her passages clear for singing.

DEAR READER: Your daughter is clearing her nasal passages with the aid of a saline solution and neti pot, both of which are available over the counter. The pot is a small plastic vessel resembling a teapot. By tipping her head to the side, she is pouring the saline through her nasal passages to keep them clear. I've not heard of the solution traveling through to the eyes and mouth, but it's possible, because the nasal passages do communicate with the eyes.

Generally considered safe, the process is often recommended by ENT specialists for those who have had sinus surgery. Those suffering from various sinus problems and allergies have also found success, and some research shows that the process does provide relief when used with other, more typical treatments.