This process is called healing crisis in natural medicine, and use to happen if your body gets to much nutrients to use to replace worn out cells and tissues. (celluliteinvestigation.com)
During nature cure, when the prana or vital force increases, the body throws out suppressed chronic diseases causing healing crisis in the form of fever, cold, cough, vomiting etc.. (yogicwayoflife.com)
This is why eating a ton of kefir when you have gut imbalance issues can sometimes trigger a temporary healing crisis from pathogen die - off in the gut. (thehealthyhomeeconomist.com)