Tadalafil is a prescription drug, commonly used to help treat men having erectile dysfunction (ED) problems, also known as impotence. Men suffering with erectile dysfunction (ED) are either unable to achieve or maintain an erection leading to sexual satisfaction. generic cialis does not cure erectile dysfunction or impotence but generic cialis does help boost the body's natural mechanisms, which lead to an erection. In clinical trials cialis achieved a success rate of as high as 92% in treating male impotence or ED. Tadalafil has given many men the ability and confidence to once again enjoy their sex lives.