Abstract: A modified alkali metal or ammonium huminate being made from molecules of the group consisting of ##STR1## wherein R.sub.1, R.sub.3 and R.sub.4 are individually hydrogen or --OH, R.sub.2 is ##STR2## or --CH.sub.2 -- and R.sub.5 and R.sub.6 are individually selected from the group consisting of hydrogen, --OH and --OCH.sub.3, with the proviso that R.sub.4, R.sub.5 and R.sub.6 are not all hydrogen at the same time and their preparation and their medical uses.

Abstract: Physiologically active, non-toxic, non-teratogenic and non-mutagenic huminates produced by oxidation of polyvalent phenols in aqueous alkaline medium at a reaction temperature under 40.degree. C., the pH value of the reaction medium always being over 9.0 during the oxidation and the supply of oxidant being proportioned so that the content of the quinones corresponding to the polyvalent phenols is always less than 0.5%, based on the polyvalent phenols used, and that the oxidation reaction is stopped when the quinone concentration decreases despite oxidant supply.

Abstract: A method of protecting fish from stress comprising adding to the water in which the fish are living a sufficient amount of a low molecular weight alkali metal humate to prevent stress which decisively lowers the mortality rate.