diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 2921519e6c3..49d30addd20 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -11710,13 +11710,20 @@ function natural_search($fields, $value, $mode = 0, $nofirstand = 0)
 
 	$value = preg_replace('/\s*\|\s*/', '|', $value);
 
-	$crits = explode(' ', $value);
+	// Split criteria on ' '.
+	// For mode 3, the split is done later on the , only and not on the ' '.
+	if ($mode != -3 && $mode != 3) {
+		$crits = explode(' ', $value);
+	} else {
+		$crits = array($value);
+	}
+
 	$res = '';
 	if (!is_array($fields)) {
 		$fields = array($fields);
 	}
 
-	$i1 = 0;	// count the nb of and criteria added (all fields / criteria)
+	$i1 = 0;	// count the nb of "and" criteria added (all fields / criteria)
 	foreach ($crits as $crit) {		// Loop on each AND criteria
 		$crit = trim($crit);
 		$i2 = 0;	// count the nb of valid criteria added for this this first criteria
@@ -11771,7 +11778,7 @@ function natural_search($fields, $value, $mode = 0, $nofirstand = 0)
 							$listofcodes .= "'".$db->escape($val)."'";
 						}
 					}
-					$newres .= ($i2 > 0 ? ' OR ' : '').$field." ".($mode == -3 ? 'NOT ' : '')."IN (".$db->sanitize($listofcodes, 1).")";
+					$newres .= ($i2 > 0 ? ' OR ' : '').$field." ".($mode == -3 ? 'NOT ' : '')."IN (".$db->sanitize($listofcodes, 1, 0, 1).")";
 					$i2++; // a criteria for 1 more field was added to string
 				}
 				if ($mode == -3) {
diff --git a/test/phpunit/FunctionsLibTest.php b/test/phpunit/FunctionsLibTest.php
index 135a83de392..30fb513b859 100644
--- a/test/phpunit/FunctionsLibTest.php
+++ b/test/phpunit/FunctionsLibTest.php
@@ -1894,7 +1894,6 @@ class FunctionsLibTest extends CommonClassTest
 		return true;
 	}
 
-
 	/**
 	 * testRoundUpToNextMultiple
 	 *
@@ -1918,4 +1917,21 @@ class FunctionsLibTest extends CommonClassTest
 		$this->assertEquals(roundUpToNextMultiple(40.5, 6), 42);
 		$this->assertEquals(roundUpToNextMultiple(44.5, 6), 48);
 	}
+
+	/**
+	 * testNaturalSearch
+	 *
+	 * @return void;
+	 */
+	public function testNaturalSearch()
+	{
+		$s = natural_search("t.field", "abc def");
+		$this->assertEquals($s, " AND (t.field LIKE '%abc%' AND t.field LIKE '%def%')");
+
+		$s = natural_search("t.field", "'abc def' ghi");
+		$this->assertEquals($s, " AND (t.field LIKE '%abc def%' AND t.field LIKE '%ghi%')");
+
+		$s = natural_search("t.field", "abc def,ghi", 3);
+		$this->assertEquals($s, " AND (t.field IN ('abc def','ghi'))");
+	}
 }