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