Greetings, Welcome to Healthcaremagic. Basically tylenol contains one of very safe painkillers that are available in the market. It is used by a majority of patients who have some or the other cause of pain and has a good safety profile.But not matter how safe a medicine is , if you don t take it as directed then it will cause problems. In your case you have taken too many of the tablets together. Although the total dose is not near the toxic dose ,but taking it together cause gastric and intestinal problems like yours. It generally causes gastric inflammation which is manifested by increased acid secretion and stomach pains , similarly when the tablets reach intestines it causes pain and diarrhea. Fortunately there is nothing to worry about. Diarrhea will settle on its own in some time . During that period it is advised to take plenty of fluids and fresh juices in order to avoid getting dehydrated. Secondly you should also take capsules that are called as proton pump inhibitors which will reduce acid secretion and hence reduce the pain due to gastric problems. I hope the answer was helpful . In case you need any further assistance feel free to contact in writing. Regards. Dr Talal Hussain