The invention relates to a gaseous composition containing an effective amount of argon gas for use, by inhalation, in preventing or treating a deficiency or failure of at least one peripheral organ in a patient. Preferably, it contains between 15 and 80% by volume of argon, and oxygen, preferably at least 21% by volume of oxygen. The organ deficiency or failure thus treated is transient, preferably from less than one hour to a plurality of days or weeks, or definitive. The organ concerned may be the liver, the kidneys or the lungs.