diff --git a/include/CoolPropLib.h b/include/CoolPropLib.h
index 8000bf60..fb0d1a2f 100644
--- a/include/CoolPropLib.h
+++ b/include/CoolPropLib.h
@@ -146,7 +146,7 @@
     EXPORT_CODE double CONVENTION K2F(double T_K);
     /** \brief Get the index for a parameter "T", "P", etc.
      * 
-     * @returns index The index as a long
+     * @returns index The index as a long.  If input is invalid, returns -1
      */
     EXPORT_CODE long CONVENTION get_param_index(const char *param);
     /** \brief Redirect all output that would go to console (stdout) to a file
diff --git a/src/CoolPropLib.cpp b/src/CoolPropLib.cpp
index 06d6439f..8cf8bd0d 100644
--- a/src/CoolPropLib.cpp
+++ b/src/CoolPropLib.cpp
@@ -228,7 +228,12 @@ EXPORT_CODE void CONVENTION set_debug_level(int level){
     CoolProp::set_debug_level(level);
 }
 EXPORT_CODE long CONVENTION get_param_index(const char * param){
-    return CoolProp::get_parameter_index(param);
+    try{
+        return CoolProp::get_parameter_index(param);
+    }
+    catch(std::exception &){
+        return -1;
+    }
 }
 EXPORT_CODE long CONVENTION get_global_param_string(const char *param, char * Output, int n)
 {
@@ -249,7 +254,12 @@ EXPORT_CODE long CONVENTION get_global_param_string(const char *param, char * Ou
 }
 EXPORT_CODE long CONVENTION get_parameter_information_string(const char *param, char * Output, int n)
 {
-    int key = CoolProp::get_parameter_index(param);
+    try{
+        int key = CoolProp::get_parameter_index(param);
+    }
+    catch(std::exception &){
+        return 0;
+    }
     if (key >= 0){
         std::string s = CoolProp::get_parameter_information(key, Output);
         if (s.size() < static_cast<unsigned int>(n)){