A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of mescaline, N,N-dimethyltriptmine, psilocin, psilocybin, salvinorin A in hair of consumers of psychedelic vegetal material such peyote or trichocereus cacti, psilocybe mushrooms, Salvia divinorum or psychedelic beverage ayahuasca. After hair washing with methyl alcohol and diethyl ether and subsequent addition of mescaline-d9 and 3,4- methylenedioxypropylamphetamine as internal standards, hair samples were treated with 250 μl VMA-T M3 reagent for 1 h at 100°C. After cooling, 100 μl M3 extract were diluted with 400 μl water and a volume of 10 μl was injected into chromatographic system. Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5 mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.03-0.05 ng/mg depending on analyte under investigation) to 10 ng/mg hair, with an intra- and inter-assay imprecision and inaccuracy always less than 15% and an analytical recovery between 79.6% and 97.4%, depending on the considered analyte. Using the validated method, mescaline was found in concentration range of 0.08 to 0.13 ng/mg in hair of peyote smokers, 3.2 ng salvinorin A per mg hair were determined in hair from a Salvia divinorum smoker, 5.6 ng N,N-dimethyltriptmine per mg hair from an ayahuasca user and finally 0.8 ng psilocybin per ng hair of a psilocybe consumer.