The invention related to a composition for use in cardioplegia, said composition comprising (i) esmolol and (ii) adenosine, wherein in use the concentration of said esmolol is in the range 0.3-1.5 mM, and wherein in use the concentration of said adenosine is in the range 0.1-1.5 mM. The invention also relates to methods of making and using such compositions.