<jats:title>Abstract</jats:title> <jats:p>Hyoscine has been isolated as the main alkaloid from the leaves, flowers, pericarp and seeds of Datura cornigera Hook. Noratropine occurs in the leaves, flowers and pericarp. The following alkaloids have been obtained from the roots, (—)-3α,6β-ditigloyloxytropane, 7-hydroxy-3,6-ditigloyloxytropane, hyoscine, hyoscyamine, atropine, norhyoscyamine, noratropine, 3α,6β-dihydroxytropane and the presence of others indicated. Hyoscyamine is the principal alkaloid of the whole roots but the root-wood, although giving a low yield of total alkaloids, contains a relatively high proportion of noratropine.