This paper presents the benefit-risk assessment of adding plant sterols to margarine as an illustration of the QALIBRA method and software. With the QALIBRA tool health effects, risks as well as benefits are expressed in a common metric (DALY) which allows quantitative balancing of benefits and risks of food intake. The QALIBRA software can handle uncertainties in a probabilistic simulation. This simple case study illustrates the data need and assumptions that go into a quantitative benefit-risk assessment. The assessment shows that the benefits of plant sterols added to margarine outweigh the risks, if any.