From the Manufacturer's Label:
Quercetin is a naturally occurring bioflavonoid that supports healthy histamine levels, thereby helping to sustain a balanced immune response.** Bromelain, an enzyme derived from pineapple stems, also supports healthy immune system function.** The combination of Quercetin and Bromelain therefore provides powerful immunomodulating.**
Manufactured by Now® Foods.Citrus Free. Not manufactured with yeast, wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.