Parsley is an herb which is considered to be safe when it comes to allergic infection. However, if you are taking the herb and suffering from symptoms that lead to urinary tract infection, kidney stones, GI disorders, constipation, and intestinal gas and so on, then you may be allergic to the herb. To know the infection, you are required to have a parsley allergic test in which the IgE antibodies in your blood are tested to see if you are allergic or not. A skin prick test can also be suggested but only when you are showing allergy on your skin.