ABSTRACT Diabetic ulcers are one of the chronic complications of diabetes mellitus that frequently lead to prolonged wound healing and unpleasant odor (malodor). Malodor is caused by bacterial colonization and tissue necrosis, which negatively affect patients' physical comfort, psychological well-being, and quality of life. Guava leaves (Psidium guajava L.) contain bioactive compounds such as flavonoids, tannins, saponins, and essential oils with antibacterial, anti-inflammatory, and antioxidant properties that may reduce wound odor. This study aimed to determine the effectiveness of boiled guava leaf water application in reducing the malodor level of diabetic ulcers at Aek Parombunan Public Health Center. This study employed a quantitative pre-experimental design using a one-group pretest–posttest approach. The study involved 20 patients with diabetic ulcers selected through purposive sampling. Malodor was assessed using the Teler Wound Odor Assessment Tool before and after the intervention. The intervention consisted of wound cleansing using boiled guava leaf water once daily for seven consecutive days. Data were analyzed using the Wilcoxon Signed Rank Test. The results demonstrated a significant reduction in malodor scores after the intervention (p<0.05). The application of boiled guava leaf water proved effective in reducing wound malodor and may serve as an alternative complementary therapy in diabetic wound management. Keywords: Diabetic Ulcer, Guava Leaves, Malodor, Wound Care, Complementary Therapy. ABSTRAK Ulkus diabetikum merupakan salah satu komplikasi kronis diabetes melitus yang sering menyebabkan proses penyembuhan luka berlangsung lama disertai timbulnya bau tidak sedap (malodor). Malodor pada luka terjadi akibat kolonisasi bakteri anaerob dan jaringan nekrotik yang dapat menurunkan kenyamanan, kualitas hidup, serta kondisi psikologis penderita. Daun jambu biji (Psidium guajava L.) mengandung flavonoid, tanin, saponin, dan minyak atsiri yang memiliki aktivitas antibakteri, antiinflamasi, serta antioksidan sehingga berpotensi mengurangi malodor pada luka. Penelitian ini bertujuan mengetahui efektivitas penerapan air rebusan daun jambu biji terhadap penurunan tingkat malodor pada luka penderita ulkus diabetikum di Puskesmas Aek Parombunan. Penelitian menggunakan desain pre-eksperimental dengan pendekatan one group pretest-posttest. Sampel penelitian sebanyak 20 penderita ulkus diabetikum yang dipilih menggunakan teknik purposive sampling. Tingkat malodor diukur menggunakan Teler Wound Odor Assessment Tool sebelum dan sesudah intervensi. Intervensi dilakukan dengan membersihkan luka menggunakan air rebusan daun jambu biji satu kali sehari selama tujuh hari berturut-turut. Analisis data menggunakan uji Wilcoxon Signed Rank Test. Hasil penelitian menunjukkan adanya penurunan skor malodor yang bermakna setelah pemberian air rebusan daun jambu biji (p<0,05). Penerapan air rebusan daun jambu biji efektif menurunkan tingkat malodor pada luka ulkus diabetikum sehingga dapat digunakan sebagai terapi komplementer dalam perawatan luka diabetik. Kata Kunci: Ulkus Diabetikum, Daun Jambu Biji, Malodor, Perawatan Luka, Terapi Komplementer