Tylenol Side Effects: Common, Severe, Long Term – Drugs.com

In general, acetaminophen (the active ingredient contained in Tylenol) is well-tolerated when administered in therapeutic doses. The most commonly reported adverse reactions have included nausea, vomiting, constipation. Injection site pain and injection site reaction have been reported with the IV product.[Ref]

Tylenol Side Effects: Common, Severe, Long Term – Drugs.com

Click on link to see all negative side effects.