I need help to understand what might be the possible cause of frequent diarrhea that my father has. He is 75 years old and has high BP from last 10-15 years. He has a pacemaker implant (in 2011) and 2 stents (in 2013) for his heart related issues. He also has light bronchial asthma from last many years and recently Alzheimers. He is on medication for all the above ailments and is quite stable with active lifestyle. He also does regular yoga morning and evening. He is teetotaller, vegetarian and his diet comprises food with very low oil. The problem is that from last 2 years he gets sudden diarrhea, with high fever and loss of body fluids. We need to admit him to a nearby clinic for glucose and antibiotic drips and he recovers in 2-3 days and gets discharged. Blood tests and stool tests during his stay at the clinics have not revealed anything serious and he gets well with regular antibiotics such as Metronidazole or Ornof. In 2012, this happened once in about 4-5 months. Now the frequency has increased and he gets these loose motions every 2-3 months. The increasing frequency of this symptom is worrying us and we need to know if there is any deeper cause for this. What kind of investigations do we need to do and what kind of treatment will help. thanks in advance.