Saint Paul's thorn in the flesh has been the subject of much controversy in medical, historical and religious literature. It was crucial for the development of Paul's theology and, therefore, its study is important for a better understanding of early Christianity. The purpose of this article is to review the available evidence on this issue, perform a historical and medical critical analysis and suggest plausible diagnosis that have not been previously published in scientific literature. Our research on primary sources seem to indicate that in 41-42 AD Paul of Tarsus developed a clinical picture with a pain similar to that of a thorn injury and bad physical appearance. It could also have a chronic course with a limited number of relapses an...