In recent years, there has been a growing focus among consumers on their health, particularly regarding the consumption of fruits and vegetables rich in nutrients. The Mekong region in Vietnam offers an intriguing environment for investigating the potential of wild edible plants as both food and medicine, given the abundance and diversity of flora in this area. The current study aimed to evaluate the useful plant resources, and nutritional compositions, phytochemical contents, antioxidant activities of some edible plants, including Flemingia macrophylla (Willd.) Merr., Indigofera tinctoria L., Crypteronia paniculata Blume, Blumea balsamifera (L.) DC., Magnolia citrata Noot. & Chalermglin, Cratoxylum formosum subsp. pruniflorum (Kur) Gogelein, and Oroxylum indicum (L.) Kurz, in the Mekong region belonging to Vietnam based on the knowledge of the Mnong and Ede ethnic groups living around this area. Our data found that the useful plants are 71 species belonging to 56 genera and 32 families of vascular plants; the stem bark of Crypteronia paniculata Blume was relatively poor in nutritional composition compared to the other seven samples, while the leaf of Oroxylum indicum (L.) Kurz was highly rich in moisture content, crude protein content, total energy, potassium, sodium, and magnesium. Intriguingly, while total phenolic and total flavonoid contents were observed to be highest in Cratoxylum formosum subsp. pruniflorum (Kurz) Gogelein and Oroxylum indicum (L.) Kurz, respectively, antioxidant capacity using DPPH assay and ABTS assay was observed to be greatest in Indigofera tinctoria L. These data suggest certain plants that contain high levels of proteins, carbohydrates, fibers, fats, phenols, and flavonoids might be consumed for different purposes to maintain regular bodily functions and offer protection against oxidative stress. Therefore, it is essential to highlight the importance of preserving traditional ethnomedical knowledge to prevent the loss of this valuable resource.