It has recently been debated whether it is possible or desirable to have one internationally recognised standard of "informed consent" or whether research ethics should be adapted to the culture and educational level of the study population. This study examined the attitudes of the Gambian people to consent to medical research, and evaluated the informed consent process used in a major efficacy trial of a Haemophilus influenzae vaccine. Consent was requested after parents had received a verbal explanation and an information sheet which described the vaccine trial in a local language. A semi-structured interview was conducted with 137 acceptors and 52 refusers. Certain points of knowledge were recalled well by the acceptors; 90% knew the purpose of the vaccine was to prevent disease, but the placebo control design was understood by only 10%. The prime motive for consenting was to receive the HIB vaccine (93%) and that for refusing was that the vaccine was experimental (35%) and might have unknown side effects (29%). Although parents took advice from researchers (50%), health workers (24%), friends (16%) and family (12%), in all cases the decision was made by one of the child's parents. Only 1% of parents sought the opinion of traditional or religious leaders. The principles of informed consent, that it should be free, autonomous and informed were affirmed by this community. Therefore, in The Gambia, the international code of informed consent is appropriate.