A biological decontamination gel, consisting of a colloidal solution comprising from 5 to 30% by mass, preferably 5 to 25% by mass, still preferably 8 to 20% by mass, based on the mass of the gel, of at least one inorganic viscosifying agent: 0.5 to 10 mol/L of gel, preferably 1 to 10 mol/L of gel, of at least one active biological decontamination agent； 0.05 to 5% by mass, preferably 0.05 to 2% by mass, based on the mass of the gel, of at least one super-absorbent polymer； 0.1 to 2% by mass, based on the mass of the gel, of at least one surfactant； and the remainder of solvent.A biological decontamination method applying this gel.
