diff --git a/src/ClientPattern.cc b/src/ClientPattern.cc
index c93708a0..7cd4ce1d 100644
--- a/src/ClientPattern.cc
+++ b/src/ClientPattern.cc
@@ -169,7 +169,13 @@ std::string ClientPattern::toString() const {
     Terms::const_iterator it = m_terms.begin();
     Terms::const_iterator it_end = m_terms.end();
     for (; it != it_end; ++it) {
+
         pat.append(" (");
+        // replace special chars like ( ) and [ ] with \( \) and \[ \]
+        string orig = FbTk::StringUtil::replaceString((*it)->orig, "(", "\\(");
+        orig = FbTk::StringUtil::replaceString(orig, ")", "\\)");
+        orig = FbTk::StringUtil::replaceString(orig, "[", "\\[");
+        orig = FbTk::StringUtil::replaceString(orig, "]", "\\]");
 
         switch ((*it)->prop) {
         case NAME:
@@ -185,7 +191,7 @@ std::string ClientPattern::toString() const {
             pat.append("role=");
         }
 
-        pat.append((*it)->orig);
+        pat.append(orig);
         pat.append(")");
     }