diff --git a/src/HtmlUtils.js b/src/HtmlUtils.js
index 5bcc1340..824f59ab 100644
--- a/src/HtmlUtils.js
+++ b/src/HtmlUtils.js
@@ -22,7 +22,7 @@ var highlight = require('highlight.js');
 
 var sanitizeHtmlParams = {
     allowedTags: [
-        'h1', 'h2', 'font', // custom to matrix
+        'font', // custom to matrix. deliberately no h1/h2 to stop people shouting.
         'h3', 'h4', 'h5', 'h6', 'blockquote', 'p', 'a', 'ul', 'ol',
         'nl', 'li', 'b', 'i', 'strong', 'em', 'strike', 'code', 'hr', 'br', 'div',
         'table', 'thead', 'caption', 'tbody', 'tr', 'th', 'td', 'pre'