NyQuil does not contain Benadryl (diphenhydramine), but does have a similar medication, doxylamine. NyQuil contains the following medications:

  • Acetaminophen: An analgesic that used in the treatment of fever, headache, aches and pains.
  • Dextromethorphan: An antitussive agent to help control cough.
  • Doxylamine: A first generation antihistamine that is commonly used as a sleeping agent due to it's side effect of sedation or drowsiness.


Benadryl (diphenhydramine) is also a first generation antihistamine that can cause sedation or drowsiness. Due to this, it is often used as a sleep aide and is the active ingredient contained in ZzzQuil. It is considered to be in the same class of drugs as the doxylamine that is found in NyQuil.  It is also commonly used to treat allergies, allergic reactions and itching.


Since Benadryl and doxylamine, one of the ingredients in NyQuil, are both sedating antihistamines, they should not be taken together.  There is an increased risk of the side effects of sedation, drowsiness, confusion, coordination problems, respiratory depression (breathing problems) and dizziness.


As stated before, NyQuil does not contain Benadryl (diphenhydramine). It does however contain doxylamine, a similar first generation antihistamine that has sedative effects and can help treat insomnia.