Premixed packets of USP grade sodium chloride & sodium bicarbonate (purity level 99% or higher). Excellent cleansing prior to spraying nasal corticosteriods. pH Balanced & isotonic or hypertonic depending on the dilution. Suitable for use after sinus surgery & during pregnancy. Consult your physician with any concerns for use during pregnancy, use with children or use after surgery.Isotonic Saline is defined as 9 mg of sodium chloride per mL of water. Any concentration higher than this is defined as hypertonic. Limited research shows that a hypertonic saline solution may be more effective in reducing nasal mucosal or nasal lining congestion on a short term basis of a few hours. The theory is that hypertonic salt solution will draw water component out of the congested nasal tissue. It is possible that you may experience temporary burning or stinging with the hypertonic solution. If you experience any burning or discomfort, please use an isotonic solution. For your convenience, one NeilMed® blue packet in 240 mL of water is isotonic & one green packet in 240 mL is hypertonic.