化學發明是專利申請領域別中另一個重要的領域，醫學藥品的龐大商機是重要的推手，因為大多數藥物的活性成份為有機小分子化合物，且研發一新藥，須費時10到15年，研發經費估計高達26億美金，各大專利藥廠當然積極申請專利，保護投資。另一方面，Hatch-Waxman Act鼓勵學名藥可以盡早上市，使一般民眾能以較便宜的價格取得所需藥品。在美國藥品市場數千億美元的商機吸引下，學名藥廠積極挑戰專利藥廠之專利權。其中非顯而易知性要件認定，為雙方訴訟爭點。 然，化學發明的非顯而易知性要件認定之所以異於機械、電子、電機等技術，在於我們無法準確預測在奈米尺度的化學反應與分子的物性與化性，因而產生化學反應結果的不可預期性。而藥物研發是先從資料庫中，篩選出具一定活性的化合物作為先導化合物，經由取代基的引入、改變，或官能基的置換，結合活性與化合物結構關係（SAR），達成先導化合物結構最佳化，以快速、準確的找出候選藥物分子，進入臨床實驗。 2007年，美國聯邦最高法院在KSR案，針對非顯而易知性，重申Graham 案建立的非顯而易知性判斷法則的重要性，與重新適用顯而易知的嘗試。KSR判決後，許多文章討論KSR判決將不只針對機械組合發明，同時也將會對醫藥化學發明非顯而易知性之認定標準，產生一定的影響。 本論文研究KSR判決後， CAFC使用顯而易知的嘗試、與先導化合物分析（lead compound analysis）判斷準則，於醫藥產業化學發明專利的非顯而易知性的判決。CAFC於涉及組合藥物或配方調配案件，使用顯而易知的嘗試審查基準；使用先導化合物分析，都涉及系爭藥物中「活性成份結構」的非顯而易知性認定，CAFC針對不同類型的化學發明案件，採用了不同的審查基準。 KSR判決雖然重新啟用「顯而易知的嘗試」判斷準則，且CAFC適用「顯而易知的嘗試」的案件，亦明顯的增加。唯，本論文研究發現，於醫藥產業化學發明專利的非顯而易知性的判決，仍明顯高於對非藥品相關案件。 / Chemical invention is one of key art in patent application driving from the huge market size of medicines, in which active ingredients are organic molecules. The average cost to research and develop each successful drug is estimated to be $2.6 billion US dollars, and took 10 to 15 years. In other word, whether pharmaceutical companies can recover their investment in drug development heavily depends on the patent protection of their drugs. On the other hand, the Hatch-Waxman Act introduced in 1984 created the generic drug pathway to the market, so general public can obtain the drugs at a affordable price. However, within this framework, the validity of drug patents are often challenged by generic manufactures, mainly the "non-obviousness" requirement in patent system. During this lengthy and expensive drug discovery, chemist often entails making small modifications to lead compounds to establish structure-activity relationship (SAR) to speed up the process. Those modifications might be deemed “obvious to try”—and then studying the largely unpredictable, yet critical, resulting biological effects. In 2007, the Supreme Court of the United States, in KSR decision, reasserted that a prima facie case of obviousness may be determined by the framework set forth in Graham and "obvious to try" test. Since then, there are predictions that KSR decision will have a substantial impact in pharmaceutical and life sciences arts. This study, we examine the CAFC ruling in pharmaceutical arts regarding to "non-obviousness" issue by "obvious to try" and "lead compound analysis" test after the KSR decision. And found that the "non-obviousness" judgment of the chemical invention patent in the pharmaceutical industry was still significantly higher than that of the non-drug-related cases.