When there are no commercial available medications or therapeutic substituents, pharmacy compounding is necessary to meet the special clinical needs. However, in Taiwan, there are limited regulations or guidelines on pharmacy compounding. This article used the compounding of 0.02% chlorhexidine ophthalmic preparation as an example to illustrate the evaluation and decision process for the need of a compounding product in a medical center. A guidance for evaluation process of a compounding product was suggested in this article after comprehensively literature review.