The goal of the present work was the development of a method to determine beta-carbolines, i.e., tetrahydroharmine, harmine, and harmaline, together with N,N-dimethyltryptamine present in five different commercial tea extracts [Banisteriopsis caapi, Psychotria viridis, Peganum harmala, Mimosa tenuiflora and DC AB (commercial name)] which are used to prepare the ritualistic Ayahuasca tea beverages, that exerts psychoactive effects on the brain, due to interactions between these compounds. The analytes were extracted and preconcentrated by an optimized solid-phase extraction procedure and analysis was performed by gas chromatography coupled to mass spectrometry (GC–MS). Also, the optimization of the solid-phase extraction procedure was accomplished by evaluating different elution solvents and different proportions. Linearity was established from 0.2 to 20 µg/mL for all compounds, except for N,N-dimethyltryptamine (0.04 to 5 µg/mL), with determination coefficients above 0.99 for all analytes. The limits of quantification achieved for N,N-dimethyltryptamine and beta carbolines were 0.04 and 0.2 µg/mL, respectively. Recoveries ranged from 44 to 79%. Lastly, intra- and inter-day precision and accuracy values were considered acceptable, in agreement with the chosen guidelines. This is the first method that determined both beta-carbolines and N,N-dimethyltryptamine present in commercially available tea extracts using GC–MS.