<jats:p>In addition to phenazine, phenazine-1-carboxylic acid, phenazine-1,6-dicarboxylic acid and 2,9-dihydroxyphenazine-1-carboxylic acid a new compound, viz. 2,3,9-trihydroxyphenazine-1-carboxylic acid could be isolated from the culture medium of Pseudomonas fluorescens grown under iron deficiency with beryllium added to the culture medium. Its structure elucidation is described.