Is it ok to take benadryl (diphenhydramine) to treat my allergies? i've tried zyrtec and claritin but they don't work.

Most likely: If you're sure you have allergies (presumably you're referring to pollen, etc) and aren't allergic to any of the ingredients in brand name Benadryl or generic diphenhydramine, then sure, it's worth a try. But beware that Diphenhydramine may cause drowsiness & sleepiness as well as dry eyes, dry mouth, urinary retention & constipation. It's used in some otc to help induce sleep.

Dr Kimm agreed

Carefully: Benedryl is a first generation antihistamine and can be associated with significant sedation, while the others are second generation and are much less sedating. Taking benedryl at bedtime may be okay, but during the day, it can slow reaction time and potentially decrease ability to function.

Yes: Some people find that older antihistamines like Benadryl (diphenhydramine) work better for their allergies than the "second generation" antihistamines like zyrtec and claritin. Now, beware of the side effects like drowsiness...