Usually, the tetanus desensitization injection is administered in four doses. We start with 0.1 ml of tetanus toxoid plus 0.9 ml of saline diluted to 1 ml for intramuscular injection. After 20 minutes, we use 0.2 ml of tetanus toxoid plus 0.8 ml of saline diluted to 1 ml for another intramuscular injection. Twenty minutes later, we inject 0.3 ml of tetanus toxoid plus 0.7 ml of saline diluted to 1 ml intramuscularly. After another 20 minutes, we dilute the remaining tetanus toxoid with saline to 1 ml for the final intramuscular injection. After the injection, we observe for 30 minutes; if there is no allergic reaction, then it is complete.