Hi Thanks for your query. I appreciate your concern for the safety of Tylenol with Benadryl. Yes, it is OK to take these two medications together. You can also take these three medications together. Codeine is an opioid used to treat dry cough. Diphenhydramine is an antihistamine that reduces the symptoms of sneezing, itching, watery eyes, and runny nose. Tylenolol (Acetaminophen) is used to relieve headache, body ache and fever. But Benadryl is known to cause drowsiness and sleepiness so you must avoid driving. Hope this answers your query. Rate this answer, if you are convinced.