Humic substances are naturally occurring organic compounds formed by decomposition of organic matter and by synthetic activities of microorganisms. Humic acids, fulvic acids and humin are major components of humic substances. Oxyhumolite (oxidised young lignite) is a natural, inert and non-toxic material, which can contain up to 90 % of biochemically active humic substances. One of the top-quality oxyhumolites is in the Czech Republic. Some of the North-Bohemian oxyhumolites contain more than 80 % of humic acids with low contents of bitumen (< 0.1 %) and inorganics. Due to their structure and suitable properties, these substances appear to be applicable in detoxication of contaminants present in the environment. Natural humic substances are suitable for sorption, ion exchange and biodegradation processes.