Mainland Southeast Asia experienced a long, sustained period of foraging economy before rice and millet farming spread into this area prior to 4,000 years BP. Although hundreds of individuals from dense cemeteries are found in several hunter-gatherer sites in Guangxi, Southern China, and Northern Vietnam, dating from the early to middle Holocene (ca. 9,000–4,500 years BP), so far, little has been known about food sources in these pre-farming contexts. In particular, plant food resources have been unclear, although they likely were crucial to supporting rather large populations of hunter-gatherers in this region. To investigate this issue, micro plant remains, including starches and phytoliths, were recovered from stone tools excavated at the Cai Beo site in Ha Long Bay of coastal Northeastern Vietnam, and those findings revealed new understanding of the ancient diet. Examinations of those residues indicated that the hunter-gatherers at Cai Beo as early as 7,000–6,000 years BP exploited a broad spectrum of plants, such as taros, yams, acorns, palms, and more. This study exemplifies how maritime hunter-gatherers interfaced with the local plants and generated population growth from about 7,000 to 4,500 years BP. The results help us to conceptualize the early exploitation, management, and potential cultivation of subtropical and tropical plants over the broad geography of Asia and the Pacific before the arrival of rice and millet farming. In particular, the result validates the significance of roots and tubers in the ancient subsistence economy of Southeast Asia. Moreover, from the archaeological context of 4,500 to 4,000 years BP, the rice discovered in this study represents one of the earliest known in Mainland Southeast Asia.

The global spice trade has played an essential role in world history. However, because of poor preservation conditions, archaeobotanical remains of spices have been limited in archaeological contexts until now. This study reports evidence for spice processing from the archaeological site of Oc Eo in southern Vietnam, an entrepôt of the state of Funan that was occupied during the early centuries CE. Analysis of plant microremains recovered from the surfaces of Oc Eo grinding stone tools thought to be of South Asian origin has identified culinary spices that include turmeric, ginger, fingerroot, sand ginger, galangal, clove, nutmeg, and cinnamon. These spices are indispensable ingredients used in the making of curry in South Asia today. We suggest that South Asian migrants or visitors introduced this culinary tradition into Southeast Asia during the period of early trade contact via the Indian Ocean, commencing about 2000 years ago.

Research has generally outlined that the Neolithic East Asian farmers expanded into Southeast Asia, leading to substantial social and cultural transformations. However, the associated archaeobotanical evidence until now has been insufficient to clarify the exact timing, dispersal route, and farming package of the emergence of agriculture in Mainland Southeast Asia. To clarify these issues, the micro-plant remains of phytolith and starch from three Neolithic sites in Ha Long Bay were extracted and analyzed. This study validates the earliest evidence of co-cropping in northern Vietnam, involving the cultivation of rice together with foxtail millet at 4000 years BP or slightly earlier. Moreover, the results indicate that at least two patterns of subsistence strategy were practiced simultaneously during the initial farming phase in the region. The Trang Kenh people, a regional variant of the Phung Nguyen cultural group often have been seen as the first farmers in northern Vietnam, and they mainly practiced a cereal-based subsistence strategy with more vital cultural characteristics of southern China origin. Meanwhile, the Ha Long people, mainly composed of indigenous hunter-gatherer descendants, continued to utilize a wide range of their preferred plant resources such as taros, yams, and acorns, while they absorbed and incorporated new elements such as millet and rice into their food system. This study provides solid information to understand the diverse economic systems among different cultural groups in Vietnam.