Metronidazole 400 mg (https://www.medzsupplier.com/product/metronidazole-uk/) is a prescription-only antibiotic commonly used in the UK to treat bacterial and parasitic infections such as bacterial vaginosis, dental infections, and certain gastrointestinal conditions. It works by stopping the growth of anaerobic bacteria and protozoa. In the UK, metronidazole cannot be legally purchased over the counter; it must be prescribed by a qualified healthcare professional after an assessment. You can obtain it through a GP appointment, NHS services, or licensed private online pharmacies that require a consultation.