Hyoscine is the principal alkaloid of the aerial parts of Cyphanthera myosotidea; smaller proportions of apohyoscine, hyoscyamine/atropine, norhyoscyamine/noratropine, 6βhydroxy-hyoscyamine, scopine, tropine, possibly 3αtigloyloxytropane and a new alkaloid tentatively characterized as 3-phenylacetoxynortropane-6, 7-diol constitute the remainder of the alkaloid mixture. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.