How do people assess the severity of health problems? How do they decide whether these merit medical attention? We investigate how beliefs about psychological and physical causes of medical signs affect their perceived severity. Three studies showed that people perceive medical signs, objective and observable evidence of illnesses, as less severe if they originate from psychological rather than physical causes. For instance, participants rated the same cough as less harsh and scratchy when they believe it was caused by anxiety rather than by drinking contaminated tap water. As a result, participants were less likely to recommend care for medical signs with psychological origins, less likely to prioritize their care among multiple health problems, and reluctant to financially support scientific research for their cure.