Two new alkaloids, pegamine beta-D-glucopyranoside (1) and 2-deoxypeganylacetic acid (2), together with the novel 3,4-dihydro-4-hydroxynaphthalene-2-carboxylic acid (3), were isolated from the aerial part of Peganum nigellastrum. The structures of these compounds were elucidated on the basis of spectroscopic analyses, including 1D- and 2D-NMR, and ESI-MS/MS.