I have really bad allergies & also asthmatic, i am wondering if it is safe to take benadryl (diphenhydramine) as my allergies are unbareable, will it affect my asthma?

Better to use Clarit: Benadryl (diphenhydramine) or diphenylhydramine is a first generation antihistamine wich is quite sedating and has to be taken every 4to6 hours to be effective, while Claritin is long actong once a day, non sedating and can be taken with all other asthma meds.

Yes: Benadryl (diphenhydramine) and the older antihistamines can dry the mucus in the lungs and lead to blockage of the airways. The newer antihistamines, such as zyrtec, Claritin and Allegra would be safer. Another option for severe nasal allergies would be an intranasal corticosteroid. Flonase and Nasonex require a prescription, but Nasacort AQ is now available otc.