Hi thanks from your question. Mirena is levonorgestrel releasing intrauterine device. levonrgestrol is a steroid .All steroids cause gastric upset and Mirena is no exception.The small amount of steroids which is slowly released could cause hyperacidity and cramps. You should have got relief from symptoms after removal of Mirena ,if Mirena would have been responsible for your symptoms. But you continue to have symptoms which mean some other factor is responsible for your symptoms. Passing of black, green stool means your bleeding from your stomach or duodenum. The bleeding could be due to a gastric or duodenal ulcer or even multiple erosions caused by acid peptic disease. Gastric or duodenal ulcer can produce type of symptoms described by you. Start taking Rantac 150 mg morning evening and avoid acid stimulant factors like spicy food, cigarette and alcohol, if you’re using any one of them. Consultation with a physician is advisable who may be able to perform upper G I endoscopy on you to look for cause of your symptoms. Your stomach may have got infected by a bacteria called as H pylori which is responsible for acid peptic disease and ulcer in stomach or duodenum. He/she may treat your symptoms depending upon cause. The other possibility is you might be having irritable bowel syndrome. Hope this answers your question.