The phytotoxin produced by Burkholderia gladioli was purified and characterized. The ultraviolet and visible absorption spectrum of the phytotoxin exhibited two maxima at 260 nm and 399 nm in 80% aqueous methanol. The molecular weight of this substance was determined as 193 and the molecular formula was decided as C,H,N,O, by a high resolution FAB mass spectrometry. From these results, this substance was identified as toxollavin.