With Sinus Rinse, however, gravity plays no part and there is no need to tilt the head. Instead, the user fills the bottle with warm distilled water, mixes in a packet of isotonic sodium solution and squirts the slightly salted water gently up one nostril until the solution drips out the other side. Then she repeats it with the other nostril.

Both solutions appear to be effective. Last year, a study by researchers at the University of Michigan showed sinus patients who used a nasal rinse reported fewer symptoms than those who used over-the-counter sprays.

Dr. Mehta said NeilMed sales figures suggested that customers prefer the newer technique. He noted that Sinus Rinse represented about 65 percent of NeilMed’s sales, while the company’s neti pot products represented roughly 30 percent. The remaining 5 percent includes a variety of other products such as NasaMist, an isotonic saline spray, and NasoGel, a moisturizer.

Dr. Winston Vaughan, an ear, nose and throat specialist and co-director of the California Sinus Institute in Palo Alto, Calif., shares the medical community’s enthusiasm for NeilMed’s products. Unlike many others in his specialty, Dr. Vaughan said he was now likely to suggest in all but the worst cases that his sinusitis patients try nasal irrigation and some of these other remedies first, resorting to surgery only as a last resort.

These products “get the junk moving and decrease the amount of mucus that can potentially serve as a source of infection or blockage.” Dr. Vaughan said, adding that because the water-based solution in Sinus Rinse contains nothing more than isotonic saline, “it does not add any medication to a patient’s treatment regimen,” so there is no need to worry about how it interacts with medication.

These kinds of reviews have the Mehtas excited about the future; despite a sagging economy and a downward trend in consumer spending, Dr. Mehta said he expected growth to continue in the years ahead.

Still, the nasal irrigation market is rife with competing products, including SinuCleanse from Med-Systems in Madison, Wis.; Nasopure from BeWell Health in Columbia, Mo., and SinuPulse Elite, developed in Switzerland. Dozens of manufacturers offer neti pots, as well.