allergies
"I started using this right after starting immune therapy for indoor and outdoor (perennial) allergies.  I had been on Zyrtec and the additional dose of allergans coming from the shots made me miserable with continual sinus mucus draining/blowing; I tried taking Benadryl (on top of the Zyrtec) but that put me to sleep.  The Xyzal stopped the allergic reaction, so I'm on it now for the second month with no side effects; and very happy to have it."