diff --git a/demo.tex b/demo.tex
index 70f35e4..ac5e8e4 100644
--- a/demo.tex
+++ b/demo.tex
@@ -143,7 +143,7 @@ or show \textbf{bold} results.\end{verbatim}
         Block content.
       \end{block}
 
-      \begin{alertblock}{Altert}
+      \begin{alertblock}{Alert}
         Block content.
       \end{alertblock}
 
@@ -159,7 +159,7 @@ or show \textbf{bold} results.\end{verbatim}
         Block content.
       \end{block}
 
-      \begin{alertblock}{Altert}
+      \begin{alertblock}{Alert}
         Block content.
       \end{alertblock}