diff --git a/include/cantera/thermo/MargulesVPSSTP.h b/include/cantera/thermo/MargulesVPSSTP.h
index afa1f9084..c1af68104 100644
--- a/include/cantera/thermo/MargulesVPSSTP.h
+++ b/include/cantera/thermo/MargulesVPSSTP.h
@@ -300,6 +300,7 @@ public:
      *  @param testProb Hard-coded value. Only the value of 1 is used. It's
      *                  for a LiKCl system test to predict the eutectic and
      *                  liquidus correctly.
+     *  @deprecated To be removed after Cantera 2.2.
      */
     MargulesVPSSTP(int testProb);
 
diff --git a/include/cantera/thermo/MixedSolventElectrolyte.h b/include/cantera/thermo/MixedSolventElectrolyte.h
index b901d84ed..0b3d19b4a 100644
--- a/include/cantera/thermo/MixedSolventElectrolyte.h
+++ b/include/cantera/thermo/MixedSolventElectrolyte.h
@@ -295,6 +295,7 @@ public:
      *  @param testProb Hard-coded value. Only the value of 1 is used. It's
      *                  for a LiKCl system -> test to predict the eutectic and
      *                  liquidus correctly.
+     *  @deprecated To be removed after Cantera 2.2.
      */
     MixedSolventElectrolyte(int testProb);
 
diff --git a/include/cantera/thermo/PhaseCombo_Interaction.h b/include/cantera/thermo/PhaseCombo_Interaction.h
index 8367b4055..e4573aafa 100644
--- a/include/cantera/thermo/PhaseCombo_Interaction.h
+++ b/include/cantera/thermo/PhaseCombo_Interaction.h
@@ -368,6 +368,7 @@ public:
      *  @param testProb Hard-coded value. Only the value of 1 is used. It's
      *                  for a LiKCl system -> test to predict the eutectic and
      *                  liquidus correctly.
+     *  @deprecated To be removed after Cantera 2.2.
      */
     PhaseCombo_Interaction(int testProb);
 
diff --git a/include/cantera/thermo/RedlichKisterVPSSTP.h b/include/cantera/thermo/RedlichKisterVPSSTP.h
index 882ba1116..e5a2db136 100644
--- a/include/cantera/thermo/RedlichKisterVPSSTP.h
+++ b/include/cantera/thermo/RedlichKisterVPSSTP.h
@@ -291,6 +291,7 @@ public:
      *  @param testProb Hard-coded value. Only the value of 1 is used. It's
      *                  for a LiKCl system -> test to predict the eutectic and
      *                  liquidus correctly.
+     *  @deprecated To be removed after Cantera 2.2.
      */
     RedlichKisterVPSSTP(int testProb);
 
diff --git a/include/cantera/thermo/RedlichKwongMFTP.h b/include/cantera/thermo/RedlichKwongMFTP.h
index e24516136..31bd9d39f 100644
--- a/include/cantera/thermo/RedlichKwongMFTP.h
+++ b/include/cantera/thermo/RedlichKwongMFTP.h
@@ -61,6 +61,7 @@ public:
      *
      * @param testProb Hard -coded test problem to instantiate.
      *                 Current valid values are 1.
+     *  @deprecated To be removed after Cantera 2.2.
      */
     RedlichKwongMFTP(int testProb);
 
diff --git a/src/thermo/MargulesVPSSTP.cpp b/src/thermo/MargulesVPSSTP.cpp
index b22f87ef7..482b9d411 100644
--- a/src/thermo/MargulesVPSSTP.cpp
+++ b/src/thermo/MargulesVPSSTP.cpp
@@ -88,6 +88,8 @@ MargulesVPSSTP::MargulesVPSSTP(int testProb)  :
     formMargules_(0),
     formTempModel_(0)
 {
+    warn_deprecated("MargulesVPSSTP::MargulesVPSSTP(int testProb)",
+        "To be removed after Cantera 2.2");
 
     initThermoFile("LiKCl_liquid.xml", "");
 
diff --git a/src/thermo/MixedSolventElectrolyte.cpp b/src/thermo/MixedSolventElectrolyte.cpp
index b7bd189b5..39f04216a 100644
--- a/src/thermo/MixedSolventElectrolyte.cpp
+++ b/src/thermo/MixedSolventElectrolyte.cpp
@@ -92,6 +92,9 @@ MixedSolventElectrolyte::MixedSolventElectrolyte(int testProb)  :
     formMargules_(0),
     formTempModel_(0)
 {
+    warn_deprecated("MixedSolventElectrolyte::MixedSolventElectrolyte(int testProb)",
+        "To be removed after Cantera 2.2");
+
     initThermoFile("LiKCl_liquid.xml", "");
 
 
diff --git a/src/thermo/PhaseCombo_Interaction.cpp b/src/thermo/PhaseCombo_Interaction.cpp
index 0b3237f3b..b1a3d2459 100644
--- a/src/thermo/PhaseCombo_Interaction.cpp
+++ b/src/thermo/PhaseCombo_Interaction.cpp
@@ -87,7 +87,8 @@ PhaseCombo_Interaction::PhaseCombo_Interaction(int testProb)  :
     formMargules_(0),
     formTempModel_(0)
 {
-
+    warn_deprecated("PhaseCombo_Interaction::PhaseCombo_Interaction(int testProb)",
+        "To be removed after Cantera 2.2");
 
     initThermoFile("PhaseCombo_Interaction.xml", "");
 
diff --git a/src/thermo/RedlichKisterVPSSTP.cpp b/src/thermo/RedlichKisterVPSSTP.cpp
index 175307dd5..ae54811ed 100644
--- a/src/thermo/RedlichKisterVPSSTP.cpp
+++ b/src/thermo/RedlichKisterVPSSTP.cpp
@@ -51,6 +51,9 @@ RedlichKisterVPSSTP::RedlichKisterVPSSTP(int testProb)  :
     formRedlichKister_(0),
     formTempModel_(0)
 {
+    warn_deprecated("RedlichKisterVPSSTP::RedlichKisterVPSSTP(int testProb)",
+        "To be removed after Cantera 2.2");
+
     initThermoFile("LiKCl_liquid.xml", "");
     numBinaryInteractions_ = 1;
 
diff --git a/src/thermo/RedlichKwongMFTP.cpp b/src/thermo/RedlichKwongMFTP.cpp
index f9096406d..0c5bc3d7b 100644
--- a/src/thermo/RedlichKwongMFTP.cpp
+++ b/src/thermo/RedlichKwongMFTP.cpp
@@ -95,6 +95,8 @@ RedlichKwongMFTP::RedlichKwongMFTP(int testProb) :
     dpdV_(0.0),
     dpdT_(0.0)
 {
+    warn_deprecated("RedlichKwongMFTP::RedlichKwongMFTP(int testProb)",
+        "To be removed after Cantera 2.2");
     std::string infile = "co2_redlichkwong.xml";
     std::string id_;
     if (testProb == 1) {