Wikipedia, a free and collaborative Internet encyclopedia, has become one of the most popular sources of free information on the Internet. However, there have been concerns over the quality of online health information, particularly that on complementary and alternative medicine (CAM). This exploratory study aimed to evaluate several page attributes of articles on CAM in the English Wikipedia. A total of 97 articles were analyzed and compared with eight articles of broad categories of therapies in conventional medicine using the Mann-Whitney U test. Based on the Wikipedia editorial assessment grading, 4% of the articles attained "good article" status, 34% required considerable editing, and 56% needed substantial improvements in their content. The median daily access of the articles over the previous 90 days was 372 (range: 7-4,214). The median word count was 1840 with a readability of grade 12.7 (range: 9.4-17.7). Medians of word count and citation density of the CAM articles were significantly lower than those in the articles of conventional medicine therapies. In conclusion, despite its limitations, the general public will continue to access health information on Wikipedia. There are opportunities for health professionals to contribute their knowledge and to improve the accuracy and completeness of the CAM articles on Wikipedia.