diff --git a/doc/sphinx/cython/kinetics.rst b/doc/sphinx/cython/kinetics.rst
index ffffe4a48..46632c4f3 100644
--- a/doc/sphinx/cython/kinetics.rst
+++ b/doc/sphinx/cython/kinetics.rst
@@ -11,28 +11,28 @@ Reactions
 These classes contain the definition of a single reaction and its associated
 rate expression, indepenent of a specific `Kinetics` object.
 
-.. autoclass:: Reaction
+.. autoclass:: Reaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: ElementaryReaction
+.. autoclass:: ElementaryReaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: ThirdBodyReaction
+.. autoclass:: ThirdBodyReaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: FalloffReaction
+.. autoclass:: FalloffReaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: ChemicallyActivatedReaction
+.. autoclass:: ChemicallyActivatedReaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: PlogReaction
+.. autoclass:: PlogReaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: ChebyshevReaction
+.. autoclass:: ChebyshevReaction(reactants='', products='')
    :no-undoc-members:
 
-.. autoclass:: InterfaceReaction
+.. autoclass:: InterfaceReaction(reactants='', products='')
    :no-undoc-members:
 
 Auxilliary Reaction Data
diff --git a/interfaces/cython/cantera/reaction.pyx b/interfaces/cython/cantera/reaction.pyx
index 0e3451c25..5a262b04c 100644
--- a/interfaces/cython/cantera/reaction.pyx
+++ b/interfaces/cython/cantera/reaction.pyx
@@ -17,6 +17,11 @@ cdef class Reaction:
     A class which stores data about a reaction and its rate parameterization so
     that it can be added to a `Kinetics` object.
 
+    :param reactants:
+        Value used to set `reactants`
+    :param products:
+        Value used to set `products`
+
     The static methods `listFromFile`, `listFromCti`, and `listFromXml` can be
     used to create lists of `Reaction` objects from existing definitions in the
     CTI or XML format. All of the following will produce a list of the 325
@@ -40,10 +45,14 @@ cdef class Reaction:
     """
     reaction_type = 0
 
-    def __cinit__(self, *args, init=True, **kwargs):
+    def __cinit__(self, reactants='', products='', init=True, **kwargs):
         if init:
             self._reaction.reset(newReaction(self.reaction_type))
             self.reaction = self._reaction.get()
+            if reactants:
+                self.reactants = reactants
+            if products:
+                self.products = products
 
     cdef _assign(self, shared_ptr[CxxReaction] other):
         self._reaction = other
diff --git a/interfaces/cython/cantera/test/test_kinetics.py b/interfaces/cython/cantera/test/test_kinetics.py
index c4a830069..164527a02 100644
--- a/interfaces/cython/cantera/test/test_kinetics.py
+++ b/interfaces/cython/cantera/test/test_kinetics.py
@@ -645,9 +645,7 @@ class TestReaction(utilities.CanteraTest):
         self.assertEqual(eq1, eq2)
 
     def test_elementary(self):
-        r = ct.ElementaryReaction()
-        r.reactants = {'O':1, 'H2':1}
-        r.products = {'H':1, 'OH':1}
+        r = ct.ElementaryReaction({'O':1, 'H2':1}, {'H':1, 'OH':1})
         r.rate = ct.Arrhenius(3.87e1, 2.7, 6260*1000*4.184)
 
         gas2 = ct.Solution(thermo='IdealGas', kinetics='GasKinetics',
@@ -676,9 +674,7 @@ class TestReaction(utilities.CanteraTest):
                         self.gas.net_rates_of_progress[1])
 
     def test_falloff(self):
-        r = ct.FalloffReaction()
-        r.reactants = 'OH:2'
-        r.products = 'H2O2:1'
+        r = ct.FalloffReaction('OH:2', 'H2O2:1')
         r.high_rate = ct.Arrhenius(7.4e10, -0.37, 0.0)
         r.low_rate = ct.Arrhenius(2.3e12, -0.9, -1700*1000*4.184)
         r.falloff = ct.TroeFalloff((0.7346, 94, 1756, 5182))