The Internet is a potential source of information for practitioners and researchers of pharmaceutical sciences. Despite its explosive growth and popularity, pharmacists and other health care providers have been slow to use the Internet as a source of clinical information. We have identified and evaluated several sites available on the Internet that are devoted to providing information related to professional practice, pharmacotherapy, and toxicology. We have concerns, however, regarding the quality of the available information and advise users to be cautious in using the data they obtain.