Method for the industrial purification of the biologically active phycotoxins neosaxitoxin, saxitoxin and gonyaulatoxins from cyanobacteria, said method comprising the steps of: a) providing a as a source of phycotoxins, namely a cyanobacterial clone culture, which is separated into a culture medium and a wet cyanobacterial cell pellet or a frozen cyanobacterial cell pellet; b) said pellet is lysed using homogenization, solvent extraction, bead mill, freeze/thaw cycles, ultrasonication or enzymatic lysis; c) the material from the cyanobacterial cell lysis obtained in step b) is subjected to a cold extraction and organic / aqueous phase separation, namely a 50% by volume of a 1:1 chloroform:methanol mixture and 50% by volume of 1 mM acetic acid, at pH between 4 and 5, and subsequently separating the organic and aqueous phases using chloroform:methanol 1:1 by volumen, which is repeated between 1 and 5 times; d) obtaining a concentrate of the aqueous phase obtained in step (c); e) centrifuging the concentrate obtained in step d) to obtain a supernatant; f) passing the supernatant through a diatomaceous earth column, and washing the column with a washing solution; then obtaining a phycotoxin eluate with an elution solution; g) the eluate from the previous step is passed through activated charcoal columns, and said activated charcoal columns are then washed with distilled water to remove the retained pigments and impurities; phycotoxins are eluted with an elution solution; h) the eluate from the previous step is passed again through a diatomaceous earth column; the columns are washed with a solution as per in step f), and phycotoxins are eluted with an extraction solution; i) the eluate from the previous step is left in an aqueous phase evaporating the organic solvents to obtain a partially purified phycotoxin extract; j) The partially purified extract from the previous step is subjected to a preparative high-performance liquid chromatography in several steps to obtain the pure biologically active phycotoxin. a) providing a as a source of phycotoxins, namely a cyanobacterial clone culture, which is separated into a culture medium and a wet cyanobacterial cell pellet or a frozen cyanobacterial cell pellet; b) said pellet is lysed using homogenization, solvent extraction, bead mill, freeze/thaw cycles, ultrasonication or enzymatic lysis; c) the material from the cyanobacterial cell lysis obtained in step b) is subjected to a cold extraction and organic / aqueous phase separation, namely a 50% by volume of a 1:1 chloroform:methanol mixture and 50% by volume of 1 mM acetic acid, at pH between 4 and 5, and subsequently separating the organic and aqueous phases using chloroform:methanol 1:1 by volumen, which is repeated between 1 and 5 times; d) obtaining a concentrate of the aqueous phase obtained in step (c); e) centrifuging the concentrate obtained in step d) to obtain a supernatant; f) passing the supernatant through a diatomaceous earth column, and washing the column with a washing solution; then obtaining a phycotoxin eluate with an elution solution; g) the eluate from the previous step is passed through activated charcoal columns, and said activated charcoal columns are then washed with distilled water to remove the retained pigments and impurities; phycotoxins are eluted with an elution solution; h) the eluate from the previous step is passed again through a diatomaceous earth column; the columns are washed with a solution as per in step f), and phycotoxins are eluted with an extraction solution; i) the eluate from the previous step is left in an aqueous phase evaporating the organic solvents to obtain a partially purified phycotoxin extract; j) The partially purified extract from the previous step is subjected to a preparative high-performance liquid chromatography in several steps to obtain the pure biologically active phycotoxin.