Serotonin receptor (5-HT7) binding assay-directed fractionation of a methanol extract of the dried roots of Angelica sinensis (Apiaceae) led to the isolation and identification of twenty-one compounds including a new phenolic ester, angeliferulate (1), and three new phthalides, 10-angeloylbutylphthalide (2), sinaspirolide (3) and ansaspirolide (4), along with seventeen known compounds, p-hydroxyphenethyl trans-ferulate (5), Z-ligustilide (6), Z-butylidenephthalide (7), senkyunolide I (8), Z-6-hydroxy-7-methoxy-dihydroligustilide (9), N-butylbenzenesulphonamide (10), 11(S),16(R)-dihydroxy-octadeca-9Z,17-dien-12,14-diyn-1-yl acetate (11), (3R,8S)-falcarindiol (12), heptadeca-1-ene-9,10-epoxy-4,6-diyne-3,8-diol (13), oplopandiol (14), 8-hydroxy-1-methoxy-, Z-9-heptadecene-4,6-diyn-3-one (15), imperatorin, ferulic acid, vanillin, stigmasterol, sucrose, and 1,3-di-linolenin. This is the first report of a sulfonamide (10) identified from a higher plant source, although its presence needs further investigation. Biosynthetic pathways for dimeric phthalides 3 and 4 are proposed. Compound 5, 7, 11, 12, 15, and imperatorin exhibited affinity toward 5-HT7 receptors in a competitive binding assay.