Product safety has become increasingly important with the rise of consumer rights in recent years. As the package is the first line of communication between the product and consumer, apart from informing consumers of the product features and functions, the ease of identification of warning signs on products becomes key to the accurate and safe use of products. Therefore, this study spent one year collecting the warning signs on products distributed in Taiwan through onsite inspection to investigate the status and approaches of warning sign use in Taiwan through analysis of 68 samples. After the focus group discussion, 37 samples were selected for the identification assessment and in-depth investigation of issues related to warning signs. Finally, the ideal design principles and suggestions are proposed. The results of research show: (1) There are 13 types of warning signs in meaning terms, and warning signs for "Do not microwave" (17.6%), "Warning: Hot Content" (13.2%) and "Take Care of Your Belongings" (13.2%) are the most diversified to confuse consumers and should thus be standardized. (2) There are 5 types of warning signs in product terms, and the warning signs for food (30.9%), household supplies (29.4%) and cleaning agents (23.5%) are the most in quantity and meanings, suggesting that these three types of products are highly user-sensitive and the signs should be clearer to prevent hazards. (3) Results of the identification assessment show only 32.43% of the samples conform to the ISO 67%, suggesting that most warning signs are ineffective. (4) Highly identifiable signs are representational and familiar in everyday life or are conventional symbols. By contrast, low identifiable symbols are too abstract, too complex or too trifling in form, with improper icon layout or associations that consumers often confuse or misjudge. These should be considered in future studies and designs.