After complicated gallbladder surgery 4 days ago the tube is draining too much bile, about a litre a day. what could cause this?

Depends: Hi, depending on where the tube is this could be normal or abnormal. If the draining tube is meant to drain the bile( eg-as a means of protecting a bile duct anastomoses) then it's normal as the liver can produce large quantities of bile. On the other hand if this tube is in the abdominal cavity ; is just supposed to drain excess fluid then it indicates a bile leak ; is abnormal. Talk 2 surgeon.