St Catherine died in Rome, the spring of 1380, at the age of thirty-three. Given that Jesus is said to have died at the same age, and Catherine's idol Mary Magdalen is said to have fasted for thirty-three years, this may imply a self-staged suicide from lack of food intake. 
Over the years Catherine had eaten less and less, finding no nourishment in earthly food. Instead she received the Holy Communion virtually on a daily basis. This extreme fasting appeared unhealthy in the eyes of the clergy and her own sisterhood, and her confessor, Raymond of Capua, feared a scandal and so ordered her to eat properly. But Catherine claimed that she was unable to, describing her inability to eat as an infermita, illness. She would throw up what she swallowed, and suffered severe stomach pains, which she bore with patience as another penalty. She waited on the poor, serving them food at peculiar hours, and sought nourishment from them. Raymond describes how she would drink pus from the infected wound of one of her patients. She told Raymond, "As long as I have lived, I have never tasted sweeter or more exquisite food and drink." Similarly she sucked up the spittle from a dying woman with a gurgling chest. These episodes seemed a turning point; after this, she could no longer digest normal food. Her food intake was pus and Holy Communion.