OBJECTIVES: We examined whether misleading information (i.e. misinformation) may promote symptom reporting in non-clinical participants. DESIGN: A test-retest study in which we collected baseline data about participants' psychological symptoms and then misinformed them that they had rated two target symptoms relatively highly. During an interview, we determined whether participants would notice this misinformation and at direct and one-week follow-up, we evaluated whether the misinformation would exacerbate retest measures of the same symptoms. SETTING: A psychological laboratory. PARTICIPANTS: A total of 78 undergraduate students. MAIN OUTCOME MEASURES: Participants' scores on a widely used self-report measure of psychological symptoms. RESULTS: We found that most participants (63%) were blind to the discrepancies between their original symptom ratings and the upgraded scores they were misinformed with. Furthermore, at the one-week follow-up retest, blind participants revised their symptom ratings in the direction of the misinformation (i.e. they increased their ratings of these symptoms). CONCLUSION: Introspective monitoring of common psychological symptoms is poor and this creates an opportunity for misinformation and symptom escalation. Our finding bears relevance to theories about the iatrogenic amplification of medically unexplained symptoms.