A lab experiment was conducted in France to evaluate the impact of health information on consumers' choices for functional food. Successive messages revealing benefits and uncertainties of consuming yoghurts with added plant sterols for reducing cholesterol were delivered. Results show a significant and positive influence of the message linked to the cholesterol reduction on willingness to pay, even for participants without cholesterol. However participants expressed little interest in information about potential risks and scientific uncertainties, since their impacts on willingness to pay are not always statistically significant. An econometric estimation shows a significant link between the change in willingness to pay and the perception by participants regarding the scientific validity linked to the sterols.