Neti pots, which help cleanse nasal passages, can ease the symptoms of sinusitis, allergies and chronic headaches. Jean Kim, MD, of Johns Hopkins University School of Medicine in Baltimore, says overuse can risk irritating the middle ear but adds that research has not shown what constitutes “too much.” So until science tells us how much of a good thing is a bad thing, we'll keep rinsing irritants away just once or twice a day. It's our royal flush.