St. Anthony's fire
St. Anthony's fire (also known historically as Ignis Sacer and Holy Fire) may refer to:
- Ergotism, the effect of long-term ergot poisoning, traditionally due to the ingestion of alkaloids
 - Erysipelas, an acute infection, typically with a skin rash
 - St Anthony's Fire (novel), a 1994 Doctor Who novel by Mark Gatiss
 - Shingles, a painful viral disease, also called herpes zoster
 
See also
- Saint Anthony (disambiguation)
 - St. Elmo's fire, a weather phenomenon