Marrubium vulgare L. (Lamiaceae) is used for respiratory and gastrointestinal system disorders in folk medicine. According to European Pharmacopoeia criteria, standardization of the plant is defined by its marrubiin content. In present study, phenolics, marrubiin and essential oil compositions of M. vulgare from different locations in Turkey were analyzed quantitatively by UPLC, GC and GC/MS. Besides, their cytotoxic potentials were evaluated.In the samples, forsythoside B (77-400 mg/100 g dw), arenarioside (forsythoside F) (0-241 mg/100 g dw), verbascoside (acteoside) (171-416 mg/100 g dw) and apigenin-7-O-glucoside (0-17 mg/100 g dw) were determined in different ranges. Marrubiin contents (0.58-1.46 %) of some samples were two times higher than European Pharmacopoeia standards (0.7 %). beta-Caryophyllene (7.24-20.34 %), (Z)-beta-farnesene (1.58-34.85 %), germacrene D (9.8-13.37 %), bicyclogermacrene (1.71-8.63 %) and beta-bisabolene (0-16.68 %) were detected as major compounds in essential oils. The sample from the west of Aegean Region showed cytotoxicity against human neuroblastoma (SH-SY5Y) cell lines (IC50: 59.80 mu g/mL) although it has no effect on non-cancerous NIH-3T3cell lines.This is the first report on phenolic profiles of M. vulgare populations from Turkey. Their potential as marrubiin source for pharmaceutical industry should be considered.