This course describes how consumption and products affect environmental risks and impacts on human health and on ecosystems. Based on a life cycle approach, this course will first provide an overview of the impacts generated by consumers and by the students themselves. How to carry out Life Cycle Assessment (LCA) of products and services will then be presented. For the Life Cycle Impact Assessment phase, a special focus will be given to the characterization of comparative risks of toxics and substances on human health and ecosystems. This leads to discussion of the potentials and limitations of LCA compared to other assessment tools such as risk assessment and environmental impact assessment. Practical cases studies will be taken from multiple consumption domains, from agriculture and food production up to electronic services.