diff --git a/includes/libraries/class-eqeos.php b/includes/libraries/class-eqeos.php
index 7bdc85ac..7c004ce0 100644
--- a/includes/libraries/class-eqeos.php
+++ b/includes/libraries/class-eqeos.php
@@ -352,7 +352,7 @@ class eqEOS {
 		preg_replace("/\s/", "", $infix);
 
 		//Find all the variables that were passed and replaces them
-		while((preg_match('/(.){0,1}[&$]([a-zA-Z0-9]+)(.){0,1}/', $infix, $match)) != 0) {
+		while((preg_match('/(.){0,1}[&$]([a-zA-Z0-9_]+)(.){0,1}/', $infix, $match)) != 0) {
 
 			//remove notices by defining if undefined.
 			if(!isset($match[3])) {