diff --git a/src/Cart.php b/src/Cart.php
index 12f7a463..cc254902 100644
--- a/src/Cart.php
+++ b/src/Cart.php
@@ -487,7 +487,7 @@ private function createCartItem($id, $name, $qty, $price, array $options, $taxra
             $cartItem->setQuantity($qty);
         }
 
-        if($taxrate) {
+        if(isset($taxrate) && is_numeric($taxrate)) {
             $cartItem->setTaxRate($taxrate);
         } else {
             $cartItem->setTaxRate(config('cart.tax'));