Dissemination of medical information using mobile phones is still in a nascent stage because of their limited features - lack of penetration of mobile internet, small screen size etc. We present the design of a drug QA system that could be used for providing information about medicines over short message service (SMS). We begin with a survey of the drug information domain and classify the drug related queries into a set of predefined classes. Our system uses several natural language processing tools coupled with machine learning classification techniques to process drug information related queries. We focus on developing a natural language interface allowing the user to be flexible in phrasing their queries and attain an accuracy of 81% in classifying the drug related questions. We conclude that it is feasible and cheap to deploy such a system to encourage the practice of evidence based medicine. Copyright © 2014 Inderscience Enterprises Ltd.