For informed consent, patients must understand the risks and benefits of the proposed procedure. Fifty patients undergoing total hip replacement (THR) participated in an evaluation of a newly devised information booklet. Patients' understanding of the risks and benefits of THR was assessed using a questionnaire before and after they had read the booklet. Pre-booklet patients knew on average 2 benefits of THR, compared with 3 afterwards. Twenty-two patients initially identified no alternative treatment to THR. Those who knew an alternative stated on average 1 treatment compared with 2 in the post-booklet group. Fifteen patients identified no risks of THR initially, compared with two after reading the booklet. Initially patients reported 1 risk, versus 3 after reading the booklet. Forty-eight patients thought that the booklet increased their understanding of THR and its risks. Fourteen found it upsetting, but acceptable. Forty-six patients wished to keep the booklet.