If you mean a banana-peel preparation marketed as a kidney-care remedy, be careful: there’s no good clinical evidence that banana-peel tea or similar homemade preparations “cleanse” the kidneys or treat kidney disease.
If you’d still like the recipe as a food/beverage, a simple preparation is:
- Wash a ripe banana thoroughly.
- Cut off the ends and slice the peel into pieces.
- Simmer the peel in about 2 cups (500 mL) of water for 10–15 minutes.
- Strain and let it cool.
- You can add cinnamon or a little lemon for flavor.
Important: Banana peel contains potassium, and potassium intake can matter significantly for people with kidney disease or those taking certain medications. If you have reduced kidney function, are on dialysis, or have been told to limit potassium, don’t use this regularly without asking your clinician.
If you paste the original claim/article you’re referring to, I can also check whether its “kidney remedy” claims are actually supported by evidence.