Spontaneous-Remission Effect refers to the sudden disappearance of a disorder or unexpected improvement in a disease. The recovery is unexpected because the patient was either not receiving any treatment at all or they were receiving treatment that is considered to be ineffective.
For example, if you have a cold and don’t do anything to treat it, it will usually get better in a few days. But if you eat chicken soup during that time, you may conclude that the chicken soup cured you, when really your body just recovered naturally. However, there are instances of patients with fatal diseases such as cancer who suddenly went into remission for unknown reasons.