The purpose of this study is to examine the effectiveness of consumer product warnings on modifying users' behavior in avoiding accidents，critically reviewing recent research. The product liability law，which has recently been established in Japan，seems to require the placing of warnings on products carrying potential hazards. In Japan，however，hardly any research on the effectiveness of warnings has been conducted. Therefore，data，which came from studies in nations leading the way with such a law，was analyzed. Factors hindering the effectiveness of warnings were extracted in terms of such cognitive processes as attention and active processing of warnings，comprehension and agreement with the warning message，retrieval of the message and decision-making of whether or not to comply with the message. The findings showed that the warnings actually influenced users' safety behavior and were effective to some extent. The effectiveness of the warning in the attention and active processing stage was found to be influenced by factors such as the perceived hazardousness and familiarity with the product，and in addition in the decision-making stage to be influenced by factors such as the cost of complying with the warnings，the perceived hazardousness，attitudes toward safety，and social influence. It was revealed that the factors which influence the effectiveness of warnings that resulted from the users' attributes and experience were greater in number than those that resulted from warning design. The influence of different message retrieval ways and latent hazards on the effectiveness of warnings and the influence of pictograms on elderly people were discussed.