The 5 Whys is a root cause analysis tool used to identify the underlying cause of problems. It involves asking "why" five times to get to the root cause. Some key aspects of using the 5 Whys include clearly defining the problem, asking full questions at each step, focusing on both why a defect occurred and why it was not detected earlier, and challenging identified root causes to verify they reproduce the problem. The goal is to identify the systemic root cause, not just surface explanations, through a structured questioning process.