Cialis (tadalafil) is a medication used to treat erectile dysfunction (ED) and benign prostatic hyperplasia (BPH) in men. It works by increasing blood flow to the penis, aiding in achieving and maintaining an erection. Cialis is also effective in relieving urinary symptoms associated with BPH. Unlike some ED drugs, it has a prolonged effect, lasting up to 36 hours. Typically taken as needed or daily in lower doses, Cialis is known for its flexibility and long duration of action. Common side effects include headache, indigestion, back pain, and muscle aches. Always consult a healthcare provider before use.