question: Hi! Dr. I am researching treatment for symptoms that I have had all my life. I apparently have trouble fighting off cold and respiratory illnesses or an UTI. I feel run down about 80% of the time, as it feels like my body is constantly fighting off some type of bug or virus. exercise seems to exacerbate the problem. I feel it is due to either some type of immune or allergic problem. Do you know of any tests that could determine what the problem is? I was looking to possibly take Echinacea to treat this and maybe strengthen my immune system. But being unregulated by the FDA it s hard to know which brand or how much Echinacea I would need to use safely.