diff --git a/Library/Homebrew/cmd/audit.rb b/Library/Homebrew/cmd/audit.rb
index 53f9652439..4ca541a75c 100755
--- a/Library/Homebrew/cmd/audit.rb
+++ b/Library/Homebrew/cmd/audit.rb
@@ -53,7 +53,7 @@ def audit_formula_text name, text
   end
 
   # Check for string interpolation of single values.
-  if text =~ /(system|inreplace|gsub!|change_make_var!) .* ['"]#\{(\w+)\}['"]/
+  if text =~ /(system|inreplace|gsub!|change_make_var!) .* ['"]#\{(\w+(\.\w+)?)\}['"]/
     problems << " * Don't need to interpolate \"#{$2}\" with #{$1}"
   end