Pain is subjective and therefore difficult to quantify. Questionnaires to establish a pain scale have been developed. Based on 100s of these the 5 worst, in reverse order:
Crohn's disease. A digestive tract inflammation which causes intense abominable pain.
Finger amputation. A part of the body with most nerve endings, traumatic amputation causes unbearable pain.
Childbirth. Without anesthesia the pain is acute and lasts for several hours.
The sting of the Amazonian Paraponera ant. All consuming pain for 24+ hours.
The worst is "Complex Regional Pain Syndrome". Cuased by nerve-compromising injuries it is chronic, long-term and there is no treatment.
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