diff --git a/Cantera/cxx/demos/NASA_coeffs.cpp b/Cantera/cxx/demos/NASA_coeffs.cpp
new file mode 100644
index 000000000..adce583db
--- /dev/null
+++ b/Cantera/cxx/demos/NASA_coeffs.cpp
@@ -0,0 +1,84 @@
+
+#include <cantera/Cantera.h>
+#include <cantera/IdealGasMix.h>    // defines class IdealGasMix
+
+using namespace Cantera;
+
+
+// The program is put into a function so that error handling code can
+// be conveniently put around the whole thing. See main() below.
+
+void demoprog() {
+
+    printf("\n\n**** Testing modifying NASA polynomial coefficients ****\n\n");
+
+    IdealGasMix gas("h2o2.cti","ohmech");
+    int nsp = gas.nSpecies();
+
+    int type;
+    doublereal c[15];
+    doublereal minTemp, maxTemp, refPressure;
+
+    // get a reference to the species thermo property manager
+    SpeciesThermo& sp = gas.speciesThermo();
+
+    int n, j;
+
+    // these constants define the location of coefficient "a6" in the
+    // cofficient array c. The c array contains Tmid in the first
+    // location, followed by the 7 low-temperature coefficients, then
+    // the seven high-temperature ones.
+    const int LOW_A6 = 6;
+    const int HIGH_A6 = 13;
+
+    for (n = 0; n < nsp; n++) {
+
+        printf("\n\n %s (original):", gas.speciesName(n).c_str());
+
+        // get the NASA coefficients in array c
+        sp.reportParams(n, type, c, minTemp, maxTemp, refPressure);
+
+        // print the unmodified NASA coefficients
+        printf("\n      ");
+        for (j = 1; j < 8; j++) printf("     A%d     ", j);
+        printf("\n  low:");
+        for (j = 1; j < 8; j++) printf(" %10.4E ", c[j]);
+
+        printf("\n high:");
+        for (j = 8; j < 15; j++) printf(" %10.4E ", c[j]);
+        printf("\n      ");
+
+        // modify coefficient A6 of the low-temperature polynomial
+        // Note that since we are not modifying the high-temperature
+        // polynomial, a warning will be printed about a discontinuity
+        // in enthalpy at Tmid.
+        c[LOW_A6] += 1.0e4;
+        sp.modifyParams(n, c);
+
+        sp.reportParams(n, type, c, minTemp, maxTemp, refPressure);
+
+        // print the modified NASA coefficients
+        printf("\n\n %s (modified):", gas.speciesName(n).c_str());
+        printf("\n      ");
+        for (j = 1; j < 8; j++) printf("     A%d     ", j);
+        printf("\n  low:");
+        for (j = 1; j < 8; j++) printf(" %10.4E ", c[j]);
+
+        printf("\n high:");
+        for (j = 8; j < 15; j++) printf(" %10.4E ", c[j]);
+        printf("\n      ");
+    }
+}
+     
+
+ 
+int main() {
+
+    try {
+        demoprog();
+    }
+    catch (CanteraError) {
+        showErrors(cout);
+    }
+}
+