We have succeeded in completely bleaching a humic acid, extracted from peats and carefully purified, by the action of the peroxoacids, followed by a chlorhydric or enzymic hydrolysis. The degradation products characterized by chromatographic analysis on paper, and by GLC after silylation, contain 3 reducing sugars (glucose, rhamnose, arabinose), a disaccharide and 8 amino acids among which are lysine, serine and tyrosine. The reducing sugar content of the mixture (expressed in glucose) corresponds to a yield of 65% relative to the initial product.