<s>[INST] If I have fever do I always have an infection? [/INST] The most common cause of fever is an infection. Nevertheless, there are other less frequent causes. Some reactions to medicines, allergic reactions, endocrine disorders, e.g., hyperthyroidism, and untreated tumour diseases can produce a non-infectious fever.

In these instances, the doctor will indicate the most appropriate treatment for each case. Source: CLINIC BARCELONA . Link: https://www.clinicbarcelona.org/en/assistance/be-healthy/fever/frequently-asked-questions. Field: Infectious Disease. Disease: Fever </s>