As a physician, I find hap-hazard, out-of-date medication lists carried by patients to be very troublesome. Worse, many don't carry one at all. This creates a huge risk for medication errors, especially when patients are admitted to hospitals. It also presents a great opportunity for a business that can create a simple and easy way for patients to update their lists.
The webapp I am currently developing will allow people to create and manage their medication lists online. These lists can then be shared with their physicians or with hospitals (e.g. during a hospital admission or visit to ER etc.) The next steps will be to create mobile app versions of the webapp to allow better access.