Are you on an anti-diuretic? Anti-diuretics are often prescribed for heart failure & other heart problems. Diuretics can affect your potassium levels -if you are on one that makes your body deplete potassium (such as Lasix) then bananas are Ok. But if you are on a potassium sparing diuretic, occasional bananas are Ok -just don't eat a ton of them. Your body's potassium levels are very important. Normally they don't go out of whack very easily, but when you are taking certain drugs, it is easy for them to be altered. Check your meds, then call your doctor or pharmacist to be sure.