I have really bad allergies to a lot of outside elements like pollen, ragweed, etc. I also have allergies to cats & dogs which I have and can't bear to get rid of. I tried taking allergy shots for a while which worked but were expensive, so as a cheaper alternative, I take 2 Benedryls every evening and for the most part, they work really for controlling my basic allergy systoms. I still have some flair-ups every now and then and they do not make my symptoms go away, but they do help.
One thing they are especially helpful at doing is relieving my symptoms enough to help me sleep at night. They tend to make you sleepy anyway, but there isn't much worse than waking up to a runny nose or itchy eyes in the middle of the night and the Benedryl helps to make my night's sleep much more pleasant.