Warfarin 臨床用於治療與預防心血管疾病（例如全身性栓塞、中風引發的心房顫動及靜脈血栓栓塞⋯⋯等）是一種重要的抗凝血劑，但因為warfarin 治療指數狹窄，且因warfarin 的藥理特性使得它容易與藥物或食物的產生交互作用，所以，在開始治療前需提供病患及家屬完整的衛教，於治療過程中亦須定期加強用藥指導，以減少藥物不良反應的發生。病患必須了解自身使用的藥物及飲食，特別是含有高維生素K的食物或食用油。本文描述一位女性患者有風溼性二尖瓣 (rheumatic valvular heart disease) 疾病史，長期服用warfarin 治療，因近期檢查罹患有淋巴瘤需入院接受化療療程，但在化療前，因食用紅鳳菜 (Gynura’s Deux Couleurs) 之後而導致左手臂瘀青出血，因此，懷疑warfarin 與紅鳳菜產生交互作用。
 

Warfarin is recommended for the prevention and treatment of cardiovascular disease (e.g. systemic embolism, stroke associated with atrial fibrillation and venous thromboembolism). Due to pharmacological effect, its use is limited by several factors including a narrow therapeutic range, drug-drug and drug-food interactions.Education should begin from the patient’s first dose of warfarin and needs regular reinforcement. Patients who are familiar with their medication therapy can help to reduce the risk of adverse drug events. Patients should know about their drugs and diet i.e., foods and certain oils which have higher contents of vitamin K during treatment with Warfarin. In this report, we found this patient with rheumatic valvular heart disease who underwent warfarin treatment. However, because of her newly diagnosed lymphoma, she was admitted to chemotherapy and received R-CEOPregimen. Her left arm was noted ecchymosis after taking Gynura’s Deux Couleurs. This case suggested a possible interaction between warfarin and Gynura’s Deux Couleurs.