Magnoliaceae has a major center of diversification in southeastern Asia. Magnolia garrettii (Craib) V.S. Kumar () Manglietia garrettii Craib) (Thai name montha doi, montha pa) is a medium-sized tree native to montane seasonally dry forests of mainly northern Thailand, but also in Vietnam and the southern Yunnan Province of China.1-3 The evergreen tree reaches up to 30 m in height, its leaves are coriaceous and narrowly elliptic, and its dark pink flowers are considered to display the strongest coloration of all Magnoli- aceae flowers.3-6 The taxonomic rank of the genus Manglietia has been a source of controversy, and strong arguments on the basis of data from molecular analyses as well as from detailed morphological inspection have been brought to merge the genus Manglietia into Magnolia.7-11 However, previous scientific literature and the taxonomic treatment in the Flora of China4 refer mostly to the separate genus Manglietia, which is now considered a section of Magnolia.11 Reports on the chemical constituents of Magnolia, section Manglietia, of which ca. 24 species are native to Thailand, are still scant. Magnolia phuthoensis (Dandy ex. Gagnep.) V.S. Kumar () Manglietia phuthoensis Dandy ex. Gagnep.) from Vietnam was reported to contain lignan glycosides, i.e., mangliesides, together with known neolignans such as obovatol and 3-methoxymagnolol.12 Other studies reported the isolation of a dibenzopyrrocoline alkaloid from M. conifera var. chingii (Dandy) V.S. Kumar () M. chingii Dandy)13 and on the occurrence of biphenyl-type neolignans as well as the sesquiterpene lactone costunolide in the stem bark of M. garrettii.14 Reports on the medicinal use of M. garrettii could not been found in western literature. However, it is possible that its bark is used as a substitute for the important medicinally used bark of Magnolia officinalis (Magnoliae cortex, Hou-Po) from China.