Natural D- Hist includes quercetin, a powerful flavonoid, to support healthy histamine levels. Bromelain enhances the absorption of quercetin and supports mucosal tissue health. Stinging nettles leaf balance hyper-immune response and N-acetyl cysteine clear the airways by promoting normal viscosity of mucus. This powerful combination actively promotes healthy nasal and sinus passages for individuals with elevated histamine and respiratory irritation. The Natural D-Hist formula includes optimal support for nasal and sinus passageways for individuals who anticipate seasonal changes. Also available in convenient blister packs.  Natural D-Hist is a targeted blend of flavonoids, antioxidants, proteolytic enzymes and botanicals designed to provide comprehensive support for seasonal challenges caused by common environmental allergens. The formula includes quercetin, bromelain, stinging nettles leaf, and N-acetyl cysteine. The powerful combination actively promotes healthy nasal and sinus passages for individuals with elevated histamine and respiratory irritation. Suggested Use: Loading Dose: 2 capsules three times per day for 7-10 days or as recommended by your health care professional ; Maintenance: 1 or more capsules per day or as recommended by your health care professional