Can i take benadryl (diphenhydramine) with allegra?

Yes: You can take them together. If you are sensitive to the sedating effects of antihistamines, you should not take them at the same time. It would be better to take Allegra in the morning or afternoon and then Benadryl (diphenhydramine) in the evening before bed. However, if you don't feel sleepy after taking antihistamines, it would not be harmful to take them together.