A: NyQuil contains acetaminophen. Severe liver damage may occur if you: take more than four doses of NyQuil within 24 hours, take NyQuil with other drugs containing acetaminophen, consume three or more alcoholic drinks every day while taking NyQuil. If you have a severe sore throat and it persists for more than two days and is accompanied or followed by fever, headache, rash, nausea, or vomiting, consult a doctor promptly. Be sure to read the label carefully, and use NyQuil as directed. Learn more about the active ingredients in NyQuil and NyQuil SEVERE.