Dr. Gregory House is addicted to Vicodin in House M.D.
Vicodin is a prescription combination of hydrocodone and paracetamol, also called acetaminophen. In the series, House uses it to manage chronic leg pain caused by an infarction in his quadriceps muscle. His dependence becomes a major part of his character and affects both his work and relationships.
The medication is not simply a background detail. House's use leads to arguments with colleagues, attempts at treatment, professional consequences, and periods in which he tries to stop taking it. The writers use the addiction to explore the difference between his diagnostic brilliance and his inability to control parts of his own life.
Vicodin is sometimes confused with other opioid pain medicines because several appear in medical dramas. In House M.D., however, Vicodin is the specific drug most closely associated with House's addiction.