diff --git a/index.js b/index.js
index 281e6c6..d927ceb 100644
--- a/index.js
+++ b/index.js
@@ -158,6 +158,11 @@ function findEmail(_, atext, label, match) {
     return false
   }
 
+  // Do not link if label does not contain a letter.
+  if (!/[a-z]/i.test(label)) {
+    return false
+  }
+
   return {
     type: 'link',
     title: null,
diff --git a/test/base.html b/test/base.html
index 0fab254..b180827 100644
--- a/test/base.html
+++ b/test/base.html
@@ -53,6 +53,7 @@ <h2>Email autolinks</h2>
 <p><a href="mailto:a@a-b.c">a@a-b.c</a></p>
 <p>Can’t end in an underscore followed by a period: aaa@a.b_.</p>
 <p>Can contain an underscore followed by a period: <a href="mailto:aaa@a.b_.c">aaa@a.b_.c</a></p>
+<p>Can't have a domain with no letters: mdast-util-gfm-autolink-literal@1.0.1</p>
 <h2>Link text should not be expanded</h2>
 <p><a href="http://www.example.com">Visit www.example.com</a> please.</p>
 <p><a href="http://www.example.com">Visit http://www.example.com</a> please.</p>
diff --git a/test/base.md b/test/base.md
index 84ba70e..4154927 100644
--- a/test/base.md
+++ b/test/base.md
@@ -108,6 +108,8 @@ Can’t end in an underscore followed by a period: aaa@a.b_.
 
 Can contain an underscore followed by a period: aaa@a.b_.c
 
+Can't have a domain with no letters: mdast-util-gfm-autolink-literal@1.0.1
+
 ## Link text should not be expanded
 
 [Visit www.example.com](http://www.example.com) please.