Twelve alkaloids, seven of which are new, have been isolated from the root bark of Strychnos panganensis collected in Tanzania. The known alkaloids are matopensine, 16-(S)-E-isositsirikine, 12-hydroxy-11-methoxydiaboline, N-desacetylretuline and N-desacetylisoretuline. The novel alkaloids are N-desacetylspermostrychnine, 12-hydroxy-11-methoxy-nor-C-fluorocurarine, 12-hydroxy-11-methoxy-N-acetylmon-C-fluorocurarimine and four dimeric alkaloids, panganensines R, S, X and Y. Copyright (C) 1996 Elsevier Science Ltd.