A man may have erectile dysfunction if he is unable to maintain an erection or become sexually aroused. In this scenario, the penis does not contract and grow. The ingredient in Fildena100 Purple Pills, sildenafil, increases blood flow to the penile tissues in men. An erection is the natural result of a man's body responding to sexual stimulation by increasing blood flow to his penis. Meals can be taken with or without this medication. Do not chew or crush the tablet; instead, take it with water.