diff --git a/src/HtmlUtils.js b/src/HtmlUtils.js
index 5bcc134026..824f59ab20 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'