I am having cough, please suggest medicine?

Herbal medicines: Most coughs are caused by viral infections. Thus, antibiotics usually don't help- but if you have high fever, shortness of breath and/or are coughing up lots of phlegm see a doctor. In most cases herbs are very helpful for treating viral bronchial infections. Homeopathy can also help. I have had tremendous success with pelargonium sidoides and andrographis. See my comment for more info & links.

Many etiologies...: As cough has many etiologies, treatment depends on the precise diagnosis. For example, an acute cough is usually related to acute bronchitis so the bronchitis needs to be treated and the cough controlled. Chronic cough can be due to bronchospasm, gerd, post-nasal drip or some combination. To treat cough, your doctor needs to evaluate so the precise diagnosis and treatment can be done.