To assess the uptake, usage and acceptability of TOXBASE, the National Poisons Information Service internet toxicology information service. An observational study of database usage, and a questionnaire of users were undertaken involving users of TOXBASE within the UK between August 1999, when the internet site was launched, and May 2000. The main outcome measures were numbers of registered users, usage patterns on the database, responses to user satisfaction questionnaire. The number of registered users increased from 567 to 1500. There was a 68% increase in accident and emergency departments registered, a 159% increase in general practitioners, but a 324% increase in other hospital departments. Between January 2000 and the end of May there had been 60 281 accesses to the product database, the most frequent to the paracetamol entry (7291 accesses). Ecstasy was the seventh most frequent entry accessed. Altogether 165 of 330 questionnaires were returned. The majority came from accident and emergency departments, the major users of the system. Users were generally well (>95%) satisfied with ease and speed of access. A number of suggestions for improvements were put forward. TOXBASE has been extensively accessed since being placed on the internet (http://www.spib.axl.co.uk). The pattern of enquiries mirrors clinical presentation with poisoning. The system seems to be easily used. It is a model for future delivery of treatment guidelines at the point of patient care.