An ejection liquid which can be ejected stably by an inkjet method using thermal energy even in the case of containing at least one of proteins and peptides, and a method and device of discharging a liquid containing at least one of proteins and peptides, which use the ejection liquid. At least one compound having a guanidine group is added to an aqueous solution of at least one of proteins and peptides to improve its qualifications to an ejection event by an inkjet method using thermal energy.