Ayahuasca is an Amazonian plant beverage obtained by infusing the pounded stems of Banisteriopsis caapi in combination with the leaves of Psychotria viridis. P. viridis contains the psychedelic indole N,N- dimethyltryptamine (DMT). This association has a wide range of use in religious rituals around the world. In the present work, an easy, fast and non-destructive method by Nuclear Magnetic Resonance of proton (1H NMR) for quantification of DMT in ayahuasca samples was developed and validated. 2,5- Dimethoxybenzaldehyde (DMBO) was used as internal standard (IS). For this purpose, the area ratios produced by protons of DMT (N(CH3)2) at 2.70 ppm, singlet, (6H) and for DMBO (Ar(OCH3)2) at 3.80 and 3.89 ppm, doublet, (6H) were used for quantification. The lower limit of quantification (LLOQ) was 12.5 mg/mL and a good intra-assay precision was also obtained (relative standard deviation < 5.1%). The present 1H NMR method is not time consuming and can be readily applied to monitor this tryptamine in plant preparations. We believe that qNMR can be used for identification and quantification of many plant-based products and metabolites with important advantages, while comparing with other analytical techniques.