How long will it take for potassium levels to go up after stopping laxitive abuse?

Depends. : This can depend on how long laxatives were used and if any other medications that can cause potassium loss were also being taken. Also, if magnesium levels are low, this will delay potassium normalization. Ask your doctor to guide treatment and monitor potassium and magnesium levels closely. Bananas, tomatoes, potatoes, citrus, avocado, coconut water all are naturally rich sources of potassium.