diff --git a/markdown.go b/markdown.go
index c6d8b10..a0349ca 100644
--- a/markdown.go
+++ b/markdown.go
@@ -143,6 +143,7 @@ var blockTags = map[string]struct{}{
 	"output":     {},
 	"progress":   {},
 	"section":    {},
+	"summary":    {},
 	"video":      {},
 }