diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index eff006cdcd..c876916afa 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -657,6 +657,8 @@ private
     case method
     when :brew
       raise "You cannot override Formula#brew"
+    when :patch
+      raise "You probably meant `def patches`."
     when :test
       @test_defined = true
     end