Phytochemical investigation of the seeds of Althea officinalis L. (Malvaceae) led to the isolation of three new phytoconstituents, identified as n-hexacos-2-enyl-1,5-olide (altheahexacosanyl lactone), 2beta-hydroxycalamene (altheacalamene) and 5,6-dihydroxycoumarin-5-dodecanoate-6beta-D-glucopyranoside (altheacoumarin glucoside), along with the known phytoconstituents lauric acid, beta-sitosterol and lanosterol. The structures of these compounds were established on the basis of spectral analysis and chemical reactions.