A study of Cialis has led to that fact that this drug pleased not only men but many doctors as thanks to Cialis a normal function which improves the quality of erection is restored in the male body. The action of Cialis occurs with the help of increase of blood flow into penis of man which helps to gain normal erection and have full sexual intercourse. Relaxation of smooth muscles of penis and dilatation of arteries under the influence of Cialis and as a result of it the common process of affluxion of blood to penis occurs.