diff --git a/include/cantera/kinetics/Kinetics.h b/include/cantera/kinetics/Kinetics.h
index 2b94f2345..2175449cc 100644
--- a/include/cantera/kinetics/Kinetics.h
+++ b/include/cantera/kinetics/Kinetics.h
@@ -724,10 +724,12 @@ public:
     virtual void modifyReaction(size_t i, shared_ptr<Reaction> rNew);
 
     /**
-     * Return the Reaction object for reaction *i*.
+     * Return the Reaction object for reaction *i*. Changes to this object do
+     * not affect the Kinetics object until the #modifyReaction function is
+     * called.
      */
     shared_ptr<Reaction> reaction(size_t i);
-    
+
     shared_ptr<const Reaction> reaction(size_t i) const;
 
     //! Determine behavior when adding a new reaction that contains species not
diff --git a/include/cantera/thermo/Phase.h b/include/cantera/thermo/Phase.h
index f2637f247..a5330f799 100644
--- a/include/cantera/thermo/Phase.h
+++ b/include/cantera/thermo/Phase.h
@@ -713,10 +713,14 @@ public:
      */
     virtual void modifySpecies(size_t k, shared_ptr<Species> spec);
 
-    //! Return the Species object for the named species.
+    //! Return the Species object for the named species. Changes to this object
+    //! do not affect the ThermoPhase object until the #modifySpecies function
+    //! is called.
     shared_ptr<Species> species(const std::string& name) const;
 
-    //! Return the Species object for species whose index is *k*.
+    //! Return the Species object for species whose index is *k*. Changes to
+    //! this object do not affect the ThermoPhase object until the
+    //! #modifySpecies function is called.
     shared_ptr<Species> species(size_t k) const;
 
     //! Set behavior when adding a species containing undefined elements to just
diff --git a/interfaces/cython/cantera/kinetics.pyx b/interfaces/cython/cantera/kinetics.pyx
index d457d0ec3..271369918 100644
--- a/interfaces/cython/cantera/kinetics.pyx
+++ b/interfaces/cython/cantera/kinetics.pyx
@@ -79,13 +79,16 @@ cdef class Kinetics(_SolutionBase):
     def reaction(self, int i_reaction):
         """
         Return a `Reaction` object representing the reaction with index
-        ``i_reaction``.
+        ``i_reaction``. Changes to this object do not affect the `Kinetics` or
+        `Solution` object until the `modify_reaction` function is called.
         """
         return wrapReaction(self.kinetics.reaction(i_reaction))
 
     def reactions(self):
         """
-        Return a list of all `Reaction` objects
+        Return a list of all `Reaction` objects. Changes to these objects do not
+        affect the `Kinetics` or `Solution` object until the `modify_reaction`
+        function is called.
         """
         return [self.reaction(i) for i in range(self.n_reactions)]
 
diff --git a/interfaces/cython/cantera/thermo.pyx b/interfaces/cython/cantera/thermo.pyx
index ce03fe44d..57ec5e811 100644
--- a/interfaces/cython/cantera/thermo.pyx
+++ b/interfaces/cython/cantera/thermo.pyx
@@ -435,7 +435,9 @@ cdef class ThermoPhase(_SolutionBase):
         """
         Return the `Species` object for species *k*, where *k* is either the
         species index or the species name. If *k* is not specified, a list of
-        all species objects is returned.
+        all species objects is returned. Changes to this object do not affect
+        the `ThermoPhase` or `Solution` object until the `modify_species`
+        function is called.
         """
         if k is None:
             return [self.species(i) for i in range(self.n_species)]