The vast majority of coughs are caused by viruses and will not respond to antibiotics even though they might make you feel quite unwell.
Most viral coughs will cause discoloured green or yellow sputum and last 5 to 10 days; antibiotics are unlikely to help in most circumstances.
A viral cough will often last up to 3 weeks. Call 111 if you are much more short of breath and 999 if you think you are life threateningly unwell or cannot speak in more than 5 word sentences.
You may find steam treatment, taking due care or a variety of over the counter products helpful for coughs.
Please ask the pharmacist for advice.
When to seek help
Any cough over 3 weeks or with blood in the sputum warrants a discussion with a nurse practitioner or a doctor.