Toothpaste Lets Her Cuddle Kitty

Q. I have had a significant cat allergy for more than 25 years, but I recently got a cat on a trial basis after my dog died. Another dog would be just too difficult, but I like having a companion animal.
I’ve been treating symptoms such as wheezing and itchy eyes with prescription medicines (including an inhaler, eye drops and Flonase). I started brushing my teeth with Crest toothpaste for sensitive teeth after hearing a caller on your radio show say it helped his asthma. Now my allergy symptoms have almost completely disappeared. I’m only using the Flonase because I KNOW I have a cat allergy! Why is this working?
A. We were surprised when a caller told us that Crest Sensitivity Toothpaste had helped his asthma. The active ingredient is potassium nitrate (saltpeter). This compound was used long ago as a treatment for asthma and arthritis.
We doubt that there could be enough potassium nitrate in toothpaste to have much pharmacological activity, but we find your story fascinating. Changing toothpaste is certainly a low-risk approach to dealing with allergy symptoms.