Archaeobotanical research in the Upper Mun River Valley has continued for more than ten years. It is a time-consuming specialisation and particularly cumbersome in Southeast Asia, where often the more interesting archaeological plant remains are found in the small fraction (<500 microns). At the request of Prof. Charles Higham, archaeobotanical investigations were undertaken in several sites from the Upper Mun River Valley, including Ban Non Wat, Non Ban Jak and most recently, at Noen U-Loke. As the title of the talk implies, after the investigation of many samples, the central conclusion from the macroremains study may be that the people in these sites subsisted on only one plant product, rice. It appears that little else has preserved in the archaeological record from the plant world. Leafy vegetables do not preserve well when charred, but then neither do we find the pulses, which do preserve well, and have been identified in other sites in mainland Southeast Asia. We might expect a variety of economic crops to be present, especially so once the Maritime Silk Road becomes an important trading network into Southeast Asia. The weeds of rice are some of the only plants well preserved and although it provides us with a picture of the rice farming practices in the region, the question remains, what other plant products were available, consumed and used (if any)?