Uvaria rufa Blume, locally known as lelak, is an ethnomedicinal plant traditionally used in East Nusa Tenggara, Indonesia, to treat conditions such as fever, bleeding, and skin allergies. To support its development as a raw material for herbal medicines, standardization is crucial to ensure its safety, efficacy, and quality. This study aimed to establish a standardization profile to ensure the consistent quality of U. rufa bark sourced from East Nusa Tenggara. A descriptive experimental method was used to determine specific and non-specific parameters of the bark. Specific parameters included identification of the plant part (bark), macroscopic characteristics (8–10 cm long, dark brown exterior, yellow interior, fibrous texture), microscopic features (parenchyma with stone cells, sclerenchyma, cork tissue), and organoleptic properties (light brown color, slightly astringent, aromatic, fine powder). The water-soluble extractive value was 12.0160% ± 0.0090, and ethanol-soluble was 22.475% ± 0.0111. Non-specific parameters assessed safety and stability: loss on drying (7.26% ± 0.8723), moisture content (9.4% ± 0.2000), total ash content (2.601% ± 0.0002), and heavy metal levels (Pb: 0.0472 ppm, Cd: 0.0014 ppm). All results met the general requirements for herbal standardization, supporting U. rufa bark’s potential as a standardized herbal medicine ingredient.