BACKGROUND: Owing to the stigma associated with sexually transmitted infections, patients may prefer to keep their illness private, and choose instead to try self-treatment remedies from the internet. However, such remedies may prove hazardous if the sellers do not provide detailed advice on adverse effects, or on avoiding transmission and re-infection. We conducted an internet search to determine the availability of treatments for STIs and the nature of information provided by vendors of these treatments. METHODS: We conducted a systematic internet search using five different search engines in February 2007. The search term included the words "self treatment" and the name of six different common STIs. We visited the vendors' websites and recorded any information on the formulation, adverse effects, cautions, and prevention of infection. RESULTS: We identified a total of 77 treatments from 52 different companies, most of which were sold from the UK and US. The available remedies were predominantly for topical use and consisted mainly of homeopathic remedies. Only a small proportion of the web-listed products gave details on adverse effects, contraindications and interactions (22%, 25% and 9% respectively). Similarly, web vendors seldom provided advice on treatment of sexual contacts (20% of chlamydia and 25% of gonorrhea treatments) or on preventive measures (13%). Conversely, evidence of effectiveness was claimed for approximately 50% of the products. CONCLUSION: While treatments for certain STIs are widely available on the internet, purchasers of such products may potentially suffer harm because of the lack of information on adverse effects, interactions and contra-indications. Moreover, we consider the paucity of preventive health advice to be a serious omission, thereby leading to patients being needlessly exposed to, and potentially re-infected with the causative pathogens.