A new oxindole alkaloid, 21-oxogelsevirine (1), has been isolated from the MeOH extract of the stem of Gelsemium rankinii and its structure elucidated. The 1H- and 13C-nmr spectra were assigned by comparison with the other three known analogs, gelsemine (4), 21-oxogelsemine (2), and gelsevirine (3). © 1986, American Chemical Society. All rights reserved.