Purpose: To analyze the amino acid contents of some plants used in traditional medicine in Southern Sonora, Mexico by using high performance liquid chromatography (HPLC).Methods: The plant samples (Jutuki, Zizyphus obtusifolia A.Gray; Jito, Forchammeria watsonii Rose; Barchata, Lycium berlandieri Dunal; Citabaro, Vallesia glabra Link; Mangle Rojo, Rhizophora mangle L and Tatachinole, Tournefortia hartwegiana Steud) were dehydrated at room temperature and ground to a fine powder. Amino acid analysis was performed by reversed-phase HPLC. Elution was carried out with a gradient mobile phase of sodium acetate 0.1 M and methanol (9:1). Samples were derived with ophthalaldehyde (OPA) and detected by fluorescence at 360(Ex)/455(Em) wavelengths.Results: HPLC analysis resulted in a reliable detection and peak resolution. Tatachinole samples show the greater amino acid concentration (7.83 to 58.17 nM). Fifteen amino acids were detected in plant samples, with aspartic acid (Asp), glutamic acid (Glu), serine (Ser), glycine (Gly), alanine (Ala) and leucine (Leu) (43.55, 44.84, 29.60, 58.17, 43.05 and 38.73 nM, respectively) presenting the highest concentrations.Conclusion: The amino acids - Asp, Glu, Ser, Gly, Ala and Leu - are naturally involved in osmolyte synthesis, cell metabolism, ammonia detoxification, antioxidant activity and alkaloid synthesis, suggesting that the therapeutic properties of these Southern Sonora plants may have some links to their amino acid composition.Keywords: Amino acid profile, Medicinal plants, Osmolytes, Drought/saline stress