OBJECTIVE: To evaluate the quality of web-based information on cocaine use and addiction and to investigate potential content quality indicators. METHODS: Three keywords: cocaine, cocaine addiction and cocaine dependence were entered into two popular World Wide Web search engines. Websites were assessed with a standardized proforma designed to rate sites on the basis of accountability, presentation, interactivity, readability and content quality. "Health on the Net" (HON) quality label, and DISCERN scale scores aiding people without content expertise to assess quality of written health publication were used to verify their efficiency as quality indicators. RESULTS: Of the 120 websites identified, 61 were included. Most were commercial sites. The results of the study indicate low scores on each of the measures including content quality. A global score (the sum of accountability, interactivity, content quality and aesthetic criteria) appeared as a good content quality indicator. CONCLUSIONS: While cocaine education websites for patients are widespread, their global quality is poor. There is a need for better evidence-based information about cocaine use and addiction on the web. PRACTICE IMPLICATIONS: The poor and variable quality of web-based information and its possible impact on physician-patient relationship argue for a serious provider for patient talk about the health information found on Internet. Internet sites could improve their content using the global score as a quality indicator.