Viagra online is a medication used to treat erectile dysfunction (ED) in men. It contains the active ingredient sildenafil... moreViagra online is a medication used to treat erectile dysfunction (ED) in men. It contains the active ingredient sildenafil citrate, which works by increasing blood flow to the penis, allowing for a firm and lasting erection. Viagra online is available in various strengths and can be purchased online with a valid prescription. It is important to consult with a healthcare provider before taking Viagra online to ensure it is safe and appropriate for you. Common side effects may include headache, facial flushing, and upset stomach. less