In this review, the administration of y-site infusion of crystalloid fluids such as Ringer's lactate and Ringer's acetate is discussed. Incompatibility may occur, and it can manifest as haziness, development of gas, colour change, precipitation and a decline of the concentration of the drug. It can also lead to phlebitis, pulmonary embolism and even death. Information on y-site compatibility with Ringer's lactate can be found, but there is a need for further research regarding y-site compatibility with Ringer's acetate.