Radiation enteritis can be challenging to diagnose and treat. We report the case of a 44-year-old woman who was diagnosed with a squamous cell carcinoma of the cervix in 1978 and treated with hysterectomy and post-operative radiotherapy. Over the next 20 years she required multiple intestinal operations resulting in short bowel syndrome. She became symptomatic of severe hypomagnesaemia which could not be corrected with oral supplementation and which required intravenous magnesium sulfate every 5-7 days for an 11-month period. However, following 25 sessions of hyperbaric oxygen therapy, she was able to discontinue intravenous magnesium and maintain her serum magnesium level with oral treatment. Her weight and stoma output improved. For over 4 years subsequent to this therapy she has not required further intravenous magnesium although has needed temporary nutritional support. Her case is complicated by vitamin A, B and D deficiencies.