Objective: To study sunscreen product application by dermatologists and photosensitive patients in China for drawing up proper directions for most efficient use of sunscreen. Methods: Thirty-nine dermatologists and 41 photosensitive patients were enrolled in this study. They were asked to apply the cream in the same way they apply sunscreen products. The mimicking cream contained dipyridamole, which is fluorescent under Wood's light (WL). Cream distribution on skin and applied amount were visually assessed under WL using a grading scale. Results: Based on results from mimicking cream use, sunscreen application by both dermatologists and photosensitive patients was shown to be inadequate, i.e. wrongly done with the palm of the hand, unevenly distributed, an insufficient amount applied, and/or sensitive areas left uncovered. The ears, neck, and dorsum of the hands were most often left unprotected. Conclusion: Inadequate sunscreen application was found to be a common failing in both dermatologists and photosensitive patients. Suitable application was only provided on central, prominent areas, with a sharply decreasing gradient of product and low application toward lateral regions of the body as a result. Continuous education and further training programs are urgently needed to ensure the correct application of sunscreen and to provide effective sun protection.