自從西元1950 年代起，盤尼西林(penicillins) 的使用拯救了數以百萬計的感染症病人。然而在西元1945 年間，盤尼西林過敏反應被報導後，大部分臨床醫師對於曾註記盤尼西林過敏的病人，多選擇相對廣效性的抗生素作為替代治療，進而衍生許多相關問題。近年來，越來越多的研究指出多數註記為盤尼西林過敏反應的病人並沒有真正的盤尼西林過敏反應，而且盤尼西林過敏反應會隨著時間的過去而降低其後產生過敏反應的機會。文獻也指出，曾註記盤尼西林過敏的病人會增加多重抗藥微生物的感染率以及增加手術傷口感染的機會。因此重新評估臨床病人的風險層級，並評估過去當下盤尼西林過敏反應的嚴重度、時間以及耐受性，將有助於評估病人是否可以接受盤尼西林及類似結構之藥物，進而減少廣泛性抗生素的使用，達成有效的治療結果。

Since the early 1950s, penicillin has saved millions of lives, including those of children, pregnant women, and patients with sepsis, meningitis, or endocarditis, among other life-threatening infections. Penicillin G remains the only recommended treatment for the prevention of mother-to-child transmission of syphilis. The first case of anaphylaxis associated with penicillin was reported in 1945. Since then, clinicians opt to broad-spectrum antibiotics in patients reported allergy history to penicillins. However, the practice may be associated with several adverse effects in the long run. In the article, we reviewed literatures regarding penicillin allergy, and discussed three topics: 1. the current concept of penicillin allergy, 2. the impact of penicillin allergy labels, and 3. the evaluation and delabel penicillin allergy. In summary, most patients with label of penicillin allergy doesn’t have penicillin allergy. To re-evaluation of the patient’s risk level and the severity, timing and tolerance of allergy reaction was important, which could be helpful for clinicians in the decision of administration of penicillin or other similar structure antibiotics, avoiding overuse the broad-spectrum antibiotics.