Influences on the daily decision-making process of consumers are vast; encompassing internal and external factors. When the decision involves products with ethical claims an extra layer of reasoning emerges as a public good characteristic is added to the private good. Especially in the food sector an increasing number of this type of products exists. One approach to increase the purchase of those products is to nudge impulsive ethical consumption. Our study combines this approach with the concept of the “warm glow of giving”, which originates from public goods theory. The “warm glow” reflects personal gain from an act of altruism. To which extend the “warm glow” can be utilized to influence the willingness-to-pay for food items with ethical claims is the core question of this research. More detailed, our study explores prosocial and proenvironmental claims separately. The paper presents preliminary findings from a binding online experimental auction with 1000 participants in Germany randomly assigned to different treatments with varying messages. Subjects bid on chocolate with FairTrade and Rainforest Alliance claims after having received either a message appealing to their feeling of a warm glow or a message with informative content. Results are embedded in existing theory on decision-making processes.