Traditional ayahuasca can be defined as a brew made from Amazonian vine Banisteriopsis caapi and Amazonian admixture plants. Ayahuasca is used by indigenous groups in Amazonia, as a sacrament in syncretic Brazilian religions, and in healing and spiritual ceremonies internationally. The study aimed to determine concentrations of the main bio- and psychoactive components of ayahuasca used in different locations and traditions. We collected 102 samples of brews from ayahuasca-using communities. Concentrations of N,N-dimethyltryptamine (DMT), tetrahydroharmine, harmine, and harmaline were determined by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Qualitative analyses for non-traditional additives (moclobemide, psilocin, yuremamine) were performed by high resolution mass spectrometry. Higher and more variable concentrations of DMT in neoshamanic ayahuasca samples compared to indigenous samples may indicate use of higher and more variable proportions of DMT-containing admixture plants. From European samples, we found two related samples of analog ayahuasca containing moclobemide, psilocin, DMT, yuremamine, and very low concentrations of B. caapi alkaloids. Some analogs of ayahuasca (Peganum harmala, Mimosa tenuiflora) were used in Europe. No analogs were found from Brazil or Santo Daime ceremonies in Europe. We recommend awareness about the constituents of the brew and ethical self-regulation among practitioners of ayahuasca ceremonies.