This folk botany study was conducted at Hia Village, a Lue, in Pua District, Doi Tiew Village, a Hmong, and Saen Charoen Village, a Yao, in Tha Wang Pha District, Nan Province. It was found that there were 273 kinds of useful plants in 221 families and 96 phyla. They were categorized into 98 kinds as food, 167 kinds as medicinal herbs, 11 kinds as commercial crops, and 31 kinds for other purposes. One particular flora, Single Buk (Maesaglomerata K. Larsen & C.M.Hu), was found, which the Hmong boiled its roots to heal chronic ailments. What is interesting is Samutharakhodom (Sorghum vulgare var. saccharatumBoerl.). Its stalk is sugary with tougher texture and its seeds can be used as animal feed. It should be genetically improved as a raw material for sugar production. Ripe fruit of Khai Pu Yai, Nam Khai Kung and Som Kung are sweet and a little sour, suitable for making jam and their genetics should be improved. As for galangal, the Hmong and the Yao use its fruit and roots in cooking and its flower can be grilled as a chili condiment. The flower is beautiful, so it should be genetically improved for cut flowers. For medicinal herbs, the stalk of a rhizome locally called Wan Phra Chim is boiled or fermented in a local whiskey, which is believed to be an aphrodisiac among Hmong men.  Stalks of Kok and Khom Bang grass are boiled for Hmong pregnant women wanting to have a miscarriage. Roots of Phung Kaew Ku Dan are boiled for drinking or bathing to heal gonorrhea among the Hmong. The investigation also revealed that the plants were directly collected from the wild. Without additional cultivation or careful use or good management, certain plants might become extinct in the future. Furthermore, eight kinds of ferns and 256 kinds of flowering plants were also discovered, which required further studies for classification and how to utilize them seriously, so that existing natural resources can be optimally exploited.