Abstract: Objective What dose range in treatment is appropriate? Are adverse drug reactions and resistance related to dose? These three problems and their relationships were researched to seek solution to the road of reunification in this paper. Methods Study was conducted on the relationship between dose and drug effect, with gold zone as the middle range and empirical range divided into three sections, which are the key to the study design. Results The incidence of drug adverse reactions of both appeared U-shaped rule with dose, namely, with increase of the dose （mg·kg^-1·d^-1）, the adverse reaction rate first decreased and then rose, and the bottom of U-shaped curve was in the gold zone. The analysis of reasonable cost and unreasonable cost indicates resistance, and the drug dose also show U-shaped rule. Conclusion Abuse of antibiotics, adverse reactions and resistance are three major medical challenges today. Utilizing the gold zone method to determine dose is the current special breakthrough in solving the three problems.