diff --git a/ast/misc.go b/ast/misc.go
index 1e259893d..f70f8a2dc 100755
--- a/ast/misc.go
+++ b/ast/misc.go
@@ -63,10 +63,11 @@ const (
 	RepeatableRead  = "REPEATABLE-READ"
 
 	// Valid formats for explain statement.
-	ExplainFormatROW = "row"
-	ExplainFormatDOT = "dot"
-	PumpType         = "PUMP"
-	DrainerType      = "DRAINER"
+	ExplainFormatROW  = "row"
+	ExplainFormatDOT  = "dot"
+	ExplainFormatHint = "hint"
+	PumpType          = "PUMP"
+	DrainerType       = "DRAINER"
 )
 
 // Transaction mode constants.
@@ -80,6 +81,7 @@ var (
 	ExplainFormats = []string{
 		ExplainFormatROW,
 		ExplainFormatDOT,
+		ExplainFormatHint,
 	}
 )
 
diff --git a/parser_test.go b/parser_test.go
index e7a9aa05c..803e844e6 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -3700,6 +3700,7 @@ func (s *testParserSuite) TestExplain(c *C) {
 		{"EXPLAIN FORMAT = TRADITIONAL SELECT 1", true, "EXPLAIN FORMAT = 'row' SELECT 1"},
 		{"EXPLAIN FORMAT = JSON FOR CONNECTION 1", true, "EXPLAIN FORMAT = 'json' FOR CONNECTION 1"},
 		{"EXPLAIN FORMAT = JSON SELECT 1", true, "EXPLAIN FORMAT = 'json' SELECT 1"},
+		{"EXPLAIN FORMAT = 'hint' SELECT 1", true, "EXPLAIN FORMAT = 'hint' SELECT 1"},
 	}
 	s.RunTest(c, table)
 }