Mastic Gum Extract For Stomach Discomfort Mastic gum, a natural resin from the Pistacia lentiscus tree of Greece, has been used traditionally by Mediterranean cultures to support gastrointestinal health. Source Naturals Mastic Gum Extract supports a healthy stomach lining and may help relieve digestive discomfort.* 500 mg Capsule Option Available: 30, 60, 120 Suggested Use: 1 to 2 capsules daily between meals. Allergies: Contains no yeast, dairy, egg, gluten, soy or wheat.Contains no sugar, salt, preservatives, or artificialcolor, flavor or fragrance.