allergic rhinitis
"I have used this medicine since grade school for allergy and hay fever (dust, mold, pollen, etc) and find it is really big on effect and its side effect, drowsiness, doesn't seem to bother me.  This said, others that I have recommended it to say its like a tranquilizer.  For taming allergic conditions, this is great - second only to diphenhydramine in effectiveness for an OTC.  Diphenhydramine, however, has a much stronger drowsiness side effect for me.  The best news is that this is cheap!  Around $4 for 100 4mg tab doses."