Three tropane alkaloids, 1-3, were isolated from Erythroxylum caatingae, i.e., 6beta-benzoyloxy-3alpha-[(4-hydroxy-3,5-dimethoxybenzoyl)oxy]tropane (1), a new tropane alkaloid, along with the known alkaloids 3alpha,6beta-dibenzoyloxytropane (2) and 6beta-benzoyloxy-3alpha-[(3,4,5-trimethoxybenzoyl)oxy]tropane (catuabine B; 3). Their structures were determined by 2D- ((1) H and (13) C) NMR. By LC/ESI-MS/MS analysis of the fractions of alkaloids 1-3, it was possible to detect five more alkaloids, 4-8, two of these, 4 and 8, possibly being new natural products. X-Ray crystallography of the chloride derivate of 1, i.e., 6beta-benzoyloxy-3alpha-(4-hydroxy-3,5-dimethoxybenzoyloxy)tropane hydrochloride (1a) confirmed the structure of 1. Cytotoxicity was tested against the cell lines HEp-2, NCI-H292, and KB for the MeOH extract and alkaloid 3, and antitumor activity was tested against Sarcoma 180 only for the MeOH extract. CI - Copyright (c) 2011 Verlag Helvetica Chimica Acta AG, Zurich.