Are there side effects with black pepper?

possibly. One study suggested that black pepper can lead to potassium decreases ; ^ mucosal micobleeding due to ^ hydrochloric acid secretions in the stomach. Some studies have suggested that piperine contained in black pepper may carcinogenic – while other studies indicate it may be anti-carcinogenic.
Effects on what? Pepper is a spice. What are you looking to find out what it effects?