Barn dust extract to protect against allergies.

Process for the preparation of an extract of antiallergic use as a medicament, wherein the extract is prepared in the following steps: a) collecting dust dry stable, b) optionally homogenizing the dust, c) suspension of the powder optionally homogenised, in water or an aqueous buffer solution containing mono or divalent salts, selected from NaCl, Na2SO4, KCl, LiCl, MgCl2 and CaCl2, preferably a solution of 0.9% NaCl, at or below room temperature, d) possibly disintegration of the powder components, e) sedimentation of the solid components of the suspension and removal of the aqueous supernatant, constituting the supernatant after sedimentation extract, f) optionally dialysis of the aqueous supernatant where throughout the process of preparation no contribution is made heat.