diff --git a/grbl.cpp b/grbl.cpp
index 1d9376b..b03d9c1 100644
--- a/grbl.cpp
+++ b/grbl.cpp
@@ -35,7 +35,7 @@ grbl::program::program(std::string filename) {
     load_from_file(std::move(filename));
 }
 
-static auto comment_re = std::regex(R"(\(([^)]*)\))");
+static auto comment_re = std::regex(R"(^\s*\(([^)]*)\)\s*$)");
 static auto gcode_re = std::regex(R"(([a-zA-Z0-9\s.\-]+)\s*(;.*|\(([^)]*)\))?)");
 
 bool grbl::program::load_from_stream(std::istream& in) {