diff --git a/htdocs/core/lib/json.lib.php b/htdocs/core/lib/json.lib.php
index 606f6fc37bf..24464898a28 100644
--- a/htdocs/core/lib/json.lib.php
+++ b/htdocs/core/lib/json.lib.php
@@ -72,13 +72,15 @@ function dol_json_encode($elements)
 		$output = '{';
 		$last = $num - 1;
 		$i = 0;
-		foreach($elements as $key => $value)
-		{
-			$output .= '"'.$key.'":';
-			if (is_array($value)) $output.= json_encode($value);
-			else $output .= _val($value);
-			if ($i !== $last) $output.= ',';
-			++$i;
+		if (is_array($elements) && count($elements)>0) {
+			foreach($elements as $key => $value)
+			{
+				$output .= '"'.$key.'":';
+				if (is_array($value)) $output.= json_encode($value);
+				else $output .= _val($value);
+				if ($i !== $last) $output.= ',';
+				++$i;
+			}
 		}
 		$output.= '}';
 	}