diff --git a/packages/mermaid/src/docs/syntax/sequenceDiagram.md b/packages/mermaid/src/docs/syntax/sequenceDiagram.md
index 8826f6275..10d163e36 100644
--- a/packages/mermaid/src/docs/syntax/sequenceDiagram.md
+++ b/packages/mermaid/src/docs/syntax/sequenceDiagram.md
@@ -394,6 +394,12 @@ sequenceDiagram
 
 It is possible to highlight flows by providing colored background rects. This is done by the notation
 
+```
+rect COLOR
+... content ...
+end
+```
+
 The colors are defined using rgb and rgba syntax.
 
 ```