Organic matter was extracted from Podzol B horizons from nine different sites and analyzed by chemical and spectroscopic methods. The biological activity of each extract was also assessed. After purification, all extracts, which represented between 31 and 56% of the organic matter in the original soil samples, were soluble in base, acid and water, which classified them as fulvic acids. The chemical and spectroscopic data for the nine fulvic acids indicated great similarities in gross structural features and functional groups. As could be judged from the E4/E6 ratios, the acids contained few condensed ring structures. All fulvic acids contained stable free radicals and increased root initiation in bean stem segments. While the free radical content of the fulvic acids did not correlate statistically with their ability to increase root initiation, this aspect merits further investigation. The high acidity, the predominance of COOH groups and the water solubility exhibited by all fulvic acid preparations point to a significant role of these materials not only in soils and waters but also within plants.