"Q: WHAT IS ZEA MAYS and WHY IS IT IN ORIJEN?
A: The Zea Mays in ORIJEN is CORN SILK which is actually classified as an herb or botanical – not a grain. Corn Silk is NOT made from grain but rather from filaments from the flowers of female corn plant. This costly botanical features Maizenic Acid as an active ingredient and is formulated in ORIJEN diets at 300mg/kg. As corn silk does not contain corn starch or corn protein it poses absolutely no risk to dogs that may have corn allergies.
Corn silk is used to treat urinary tract infections and kidney stones and is regarded as a soothing diuretic useful for any irritation of the urinary system (a common health problem in today’s companion dogs and cats). As corn silk is used as a kidney remedy and in the regulation of fluids, this herb is believed to be helpful in treating high blood pressure and water retention.
As a well known herbal remedy, corn silk is used to treat urinary conditions in countries including the United Sates, China, Haiti, Turkey, and Trinidad. Furthermore, in China, corn silk as a component in an herbal formula is used to treat diabetes."
. . . from their FAQ section.