diff --git a/app/controllers/exercise_controller.rb b/app/controllers/exercise_controller.rb
index f19e15ba1..62be77790 100644
--- a/app/controllers/exercise_controller.rb
+++ b/app/controllers/exercise_controller.rb
@@ -5,7 +5,7 @@ class ExerciseController < ApplicationController
   before_filter :find_course, :only => [:index,:new,:create,:student_exercise_list]
 
   def index
-    # remove_invalid_exercise(@course)
+    remove_invalid_exercise(@course)
     @is_teacher = User.current.allowed_to?(:as_teacher,@course)
     if @is_teacher
       exercises = @course.exercises
@@ -231,8 +231,13 @@ class ExerciseController < ApplicationController
   end
 
   private
-  def remove_invalid_exercise
-    excercises = @course.exercises
+  def remove_invalid_exercise(course)
+    exercises = course.exercises.where("exercise_name=?","")
+    unless exercises.empty?
+      exercises.each do |exercise|
+        exercise.destroy
+      end
+    end
   end
 
   def find_exercise_and_course