There is no evidence that suggests black pepper is bad for the kidneys. Moderation might be necessary if you experience oxalate-type kidney stones, however. According to the National Kidney Foundation, patients with kidney problems are told to watch their salt intake, but pepper is no problem.
The National Kidney Foundation suggests the use of other spices to brighten up food rather than sodium. Black pepper is listed as one spice that has no impact on kidney function.
Piper nigrum is a flowering vine native to south India. Black pepper comes from its fruit, which are commonly called peppercorns. To get black pepper, the peppercorns are picked before they fully ripen. They are then cooked and dried before grinding.