Examination of the phytotoxic exudates associated with the in vitro production of thaxtomin A by Streptomyces scabies yielded four new members of this class of phytotoxins. The new compounds were characterized by spectral means as the p-hydroxyphenyl (7), 3,4-dihydroxyphenyl (8), 15-de-N-methyl (9), and 12-de-N-methyl (10) analogues of thaxtomin A (1).