The limitation on the enforceability of a patent under Article 96, Section 1, Paragraph 1 of the Korean Patent Act, which prescribes that the effects of a patent right do not extend to 'the practice of the patented invention for purposes of research or experiments', is intended to foster technological advancement by encouraging the experimental use of patented inventions. This provision, however, defines the scope excluded from the patent right’s effects only in broad and abstract terms, and the Supreme Court of Korea has yet to provide clear criteria for determining the applicability of this exception. This has led to significant controversies regarding the extent of research and experiments covered by this provision. This article examines the reasonable interpretation and application scope of this experimental use exception with a focus on pharmaceutical patented inventions and aims to present a desirable interpretation theory from the perspective of balancing and harmonizing the two elements of protecting the invention and promoting its use. Promoting the use of inventions through the experimental use exception provision should achieve a balance and harmony with the protection of inventions. Thus, the limitation on patent rights imposed by this provision should not reach a level that deteriorates the patent rights by infringing on their essential aspects. Therefore, the application scope of the experimental use exception should be assessed based on whether it unduly limits the exclusive benefits to which the patentee is entitled. Determining the applicability of the experimental use exception based on the presence of a commercial purpose or the specific nature of the experimental objective—whether it pertains to verifying patentability, investigating function, or assessing potential as an improved invention—is not appropriate. Meanwhile, pharmaceutical inventions can only enter the market after obtaining marketing authorization, which requires various experiments mandated by applicable laws. The experimental use exception under the Korean Pharmaceutical Affairs Act, as prescribed in the Korean Patent Act, is one type of exception that falls within the experimental use exception category. Additionally, when evaluating from the perspective of whether the patentee’s exclusive interests are unduly limited, the practice of patented inventions in relation to experiments for marketing authorization purposes does not unduly limit the patentee’s interests, as long as such practice does not result in the launch of a pharmaceutical product in Korea. Due to the specificity of the pharmaceutical industry, there are various forms of practicing experimental uses in the field of pharmaceutical inventions, such as cases where the subject conducting experiments is identical to or differs from the one practicing the patented invention by production, and cases where experiments are conducted domestically versus abroad. However, the Korean Patent Act does not require the practicing subjects to be identical nor does it impose limitations on the locations where experiments are conducted. Hence, each form of practicing experimental use should be evaluated from the perspective of whether it unduly limits the patentee’s interests. In this context, the impact of practicing experimental uses on the patent rights does not fundamentally differ based on individual forms of practice, and also, unless the resulting product after receiving marketing authorization, is launched in the Korean market and directly competes with the product of the patentee, it appears unlikely that the patent rights would be unduly limited regardless of specific forms of practicing experimental uses. Accordingly, the application of the experimental use exception should not be treated differently solely because specific forms of practicing experimental uses differ.