Sildenafil citrate 120 mg is a medication used for the treatment of erectile dysfunction (ED) in men. It works by inhibiting the phosphodiesterase-5 (PDE-5) enzyme, which helps relax blood vessels and increase blood flow to the penile tissues during sexual stimulation, enabling a stronger and longer-lasting erection. The 120 mg strength is considered a higher dose and may be used in cases where lower doses do not provide sufficient results, but it should only be taken under proper medical supervision. It is usually taken about 30–60 minutes before sexual activity and not more than once within 24 hours. Possible side effects may include headache, flushing, dizziness, nasal congestion, and upset stomach.