The present invention relates to a family of amidino compounds in combination with a hyperosmotic agent or a purinergic agonist for use in a method of treating respiratory disease. More specifically the invention relates to 6-amidino-2-napthyl 4-guanidinobenzoate in combination with a hyperosmotic agent or a purinergic agonist for use in a method of treating respiratory disease such as cystic fibrosis.