Can my 8yr old son take children's ibprophen an children's benadryl (diphenhydramine) together?

No problem: There should be no significant interaction between Benedryl and Motrin, which can be taken simultaneously provided the recommended doses and intervals are adhered to

Yes : Yes . He can take Motrin and Benadryl (diphenhydramine) together . No worries.

Yes: There is no interaction between the two medicines. Be sure you know the individual doses of each. Both can be given every 6 hours as needed. Also, some Benadryl (diphenhydramine) preparations have ibuprofen already in it, so make sure you don't double dose with one of these.