AI helps until you say it does

We evaluate the impact of the disclosure of artificial intelligence (AI) involvement in a charitable fundraising experiment, where participants received either AI‐generated or human‐written fundraising letters, with or without the disclosure of their origin. We find that both AI‐generated letters (whether edited by humans or not) and human‐written letters (whether edited by AI or not) significantly increase donations, producing similar positive effects. Importantly, these effects disappear when AI involvement is disclosed, regardless of whether the letters are generated or edited by AI. These findings suggest that, while AI improves the effectiveness of charitable fundraising, disclosing its use offsets this benefit.