What drug dosage range is appropriate for treatment? What drug dosage range can maximally reduce the incidence of adverse drug reaction (ADR)? The gold zone method as a new method of evidence-based medical research was proposed to study those two blind areas of drug dosage in this article. Studying the dose-effect relationship, taking gold zone as the middle range and dividing empirical range into 3 sections were the key to study design. The evidence-based survey with extremely large sample showed a U-shaped rule existing between the antibiotics’ dosage and the incidence of ADR; and the dosage in gold zone appeared at the bottom of U-shaped curve. The gold zone method for determining dosage is a special breakthrough currently for solving those two blind areas of drug dosage