The Internet is an information source. Provide information on your web site that will help them deal with pain or will help them learn about preventing heart attacks. When they find that information on the Internet and they discover that you have provided the information, and that you have a product that will help them deal with their problem, you will have them hooked. It requires a little creative thinking and a bit of hard work on your part, but in the end it can bring you customers, and lots of them. You've created a web site that potential customers will find because it contains information that they are looking for.
People use the Internet to research and buy important items like cars all the time.