The classical scientific approach is empirical. One of the favoured means of gathering quantitative data in the health and social sciences, including ethnopharmacology and medical ethnobotany, is by use of questionnaires. However, while there are numerous published articles discussing the importance of questionnaire content, the fact that questionnaires themselves may be inappropriate in a number of cultural contexts, even where literacy is not a factor, is usually ignored. In this paper, the authors will address the main issues posed by the use of questionnaire surveys, using case studies based on their own personal experiences as ethnopharmacologists ‘in the field’. The pros and cons of qualitative and quantitative research and the use of alternative means to elicit quantitative data will be discussed.