Four new β-carboline alkaloids, siliendines A–D (1‒4), and four known metabolites (5–8) were isolated from the ethanolic extract of the aerial parts of Silene seoulensis using various chromatographic methods. The structures of the new compounds were established using multiple spectroscopic approaches, with techniques such as HRESIMS and NMR, which included HSQC and HMBC. The known compounds were identified by comparing their spectra with those of the reported compounds. © 2020 Phytochemical Society of Europe