Any side effects of Chamomile are usually from the flower of the plant which can be problematic for allergy sufferers.
Chamomile may cause allergies in susceptible people because it is a flowering plant.
Chamomile is a member of the daisy family, and anyone who is allergic to other members of the daisy family, including ragweed, should not use the chamomile herb.
However if you can open a box without suffering allergic symptoms, you will probably be fine.