We have been developing web and mobile applications since 2011. The use of mobile health apps by patients is growing rapidly. It is necessary to understand the requirements of project stakeholders and industry codes, as well mastering GDPR and data protection. As an example of patient support applications, we have developed the Oral Care application for Pierre Fabre. It allows the patient to learn about teeth, or to order a tooth online, etc. It is also possible to measure tooth color over time and follow their evolution.