The propose of this study is to investigate the chemical constituents of nine Euphorbia species; namely, E. aleppica, E. eriophora, E. macroclada, E. grisophylla, E. seguieriana subsp. seguieriana, E. craspedia, E. denticulata, E. falcata and E. fistulosa by LC-MS/MS as well as their antioxidant, anticholinesterase, tyrosinase inhibitory, urease inhibitory and cytotoxic activities. Among 59 extracts prepared from the different parts of the mentioned Euphorbia species, E. seguieriana subsp. seguieriana leaf (IC50: 10.41 +/- 0.93 mu g/mL) in lipid peroxidation inhibitory by beta-carotene-linoleic acid assay exhibited the highest activity, while E. grisophylla root in DPPH free radical scavenging (IC50: 0.79 +/- 0.01 mu g/mL), E. grisophylla seed in ABTS cation radical scavenging (IC50: 8.93 +/- 0.02 mu g/mL), E. fistulosa root both in acetyl- and butyryl-cholinesterase inhibitory (53.71 +/- 1.89% and 77.63 +/- 0.60% inhibition, respectively), E. denticulata leaf in urease inhibitory (96.89 +/- 2.00% inhibition), and E. macroclada mixed in tyrosinase inhibitory (86.99 +/- 3.77% inhibition) activities. However in cytotoxic activity studies, E. denticulata against PDF fibroblast cell lines (IC50: 23.04 +/- 0.03 mu g/mL), E. craspedia against HT-29 cancer cell line (IC50: 13.74 +/- 0.02 mu g/mL), E. fistulosa against MCF-7 and DLD-1 cancer cell lines (IC50: 14.04 +/- 0.04 mu g/mL and IC50: 20.23 +/- 0.08 mu g/mL, respectively) indicated quite good activity. According to the LC-MS/MS results, these species were rich in quinic acid, malic acid and tannic acid, rutin, hesperidin and hyperoside. Incidentally, it was found that the E. eriophora possessed very strong irritating potential. A chemometric approach using principal component analysis (PCA) and hierarchical clustering analysis (HCA) techniques were also studied on collected data to reveal the relationship between chemical contents of different parts of these Euphorbia species, and their biological activities, together with regional differences. Overall, these species could be suggested as valuable sources of natural-bioactive agents for developing new functional, pharmacological and health promoting ingredients.