The aim of this work was to monitor three organic acids such as tartaric acid, malic acid and citric acid in 9 types of rural plant leaves found in Thailand such as Cowa leaf, Moringa leaf, Neem tree leaf, Noni leaf, Tamarind leaf, Soap pod leaf, Indian gooseberry leaf, Ceylon Spinach leaf and Gac leaf. The work was studied acid content in fresh rural plant leaves and effect on treatment leaves samples by boiling and freezing. The result showed that three organic acids could be detected in all fresh leaves of rural plants in different quantity. Tartaric acid, malic acid and citric acid contents were found in the range of 0.55 ± 0.01 - 685.28 ± 12.78 mg/100g, 0.50± 0.01 – 1496.64 ± 10.33 mg/100g and 0.20 ± 0.01 - 76.66 ± 9.54 mg/100g of plant leaves samples, respectively. Tartaric acid was... found highest content in Neem tree leaf and malic acid, citric acid were found highest quantity in Cowa leaf. The quantity of organic acid not depends on the taste of leaves. The organic acid content in plant leaves depend on heating time of boiling process, the cooling process as freezing could preserved organic acids in all plant leaves. Those rural plants may be used as AHA source for future acid preparation and could increase value added of rural plant leaf as a one ingredient in cosmetic industry for the future economy.