2-Amino-5-chloro-3,4-dimethoxy benzyl alcohol (ACD-MBA), a compound similar to part of the substituted tryptophan in the sporidesmin molecule was synthetized. It was coupled to bovinegamma-globulin through azo linkages and used to immunize guinea-pigs and rabbits or coupled to various bacteria and used to immunize guinea-pigs. Antibodies to ACDMBA were demonstrated by a complement fixation test. Hapten-inhibition of complement fixation showed that the anti-ACDMBA antibodies cross-reacted with sporidesmin and some derivatives of sporidesmin.