Evidence Based Medicine calls for careful evaluation of the full picture of evidence — not just the pieces that are convenient or agreeable. It demands a systematic review of the best available data, taking into account the strengths and limitations of studies, the consistency of findings, and the clinical context.

So it means, to reach conclusion about whether one treatment works or not, we need to carefully collects, evaluates, and summarizes all available evidence on a specific question or topic using a clear and structured method -- this is what we call a systematic review.