How does exposure to conspiracy theories affect voters’ political attitudes? Using an online experiment among US subjects, we show that exposure to conspiracy theories decreases voters’ trust in the domestic informational environment. Subjects were exposed to conspiracy theories that are entirely unrelated to American domestic politics, which further underscores such narratives’ danger. However, we fail to reject the null hypothesis that voters do not weigh unrelated conspiracies in their evaluation of politicians’ performance and domestic political institutions. Overall, our findings illustrate that an informational environment permeated by conspiracy theories could impede the functioning of democracy by eroding trust in information providers and undermining the credibility of political information.