diff --git a/_episodes/04-formatting.md b/_episodes/04-formatting.md
index 0e045299..bf131a72 100644
--- a/_episodes/04-formatting.md
+++ b/_episodes/04-formatting.md
@@ -363,6 +363,11 @@ for the following special blockquotes:
 >
 > A laudatory quote from a user.
 {: .testimonial}
+    
+> ## `.caution`
+>
+> A warning.
+{: .caution}
 
   </div>
 </div>