A composition for relieving a sensation of respiratory discomfort and/or for promoting natural regeneration of mucous membranes of the nasal cavity. The composition contains levomenthol at a concentration between 10 and 250 mg/l, dissolved in an aqueous ionic solution having an osmolarity at least equal to that of an aqueous solution of sodium chloride at 9 g/l. The aqueous ionic solution is pure sea water, diluted sea water, an aqueous sodium chloride solution, an aqueous sodium chloride solution further containing at least one salt found in sea water, or a mixture thereof.