They should be safe taken together for a short time, unless you have a known allergy to any of the drugs.
Mucinex is an expectorant that helps liquefy mucus and Benadryl is an anti-histamine decongestant that
relieves cough and a stuffy nose. They are often prescribed together for common colds, sinusitis and other
upper respiratory infections. If you experience any side effects such as dizziness, severe headaches,
palpitations, easy bruising, see your doctor. Hope this helps. Take care.