Erectile dysfunction (ED) is a common and treatable condition that affects many men. Cialis 10mg is a popular medication used to treat ED. It is a phosphodiesterase type 5 (PDE5) inhibitor that increases blood flow to the penis during sexual stimulation to help a man achieve and maintain an erection. Cialis 10mg is taken orally, usually 30 minutes before sexual activity and can last for up to 36 hours.