Complex sentence: It causes elevated levels of unconjugated bilirubin in the bloodstream (hyperbilirubinemia), but this normally has no serious consequences, although mild jaundice may appear under conditions of exertion or stress.
Split into simpler sentences: It causes elevated levels of unconjugated bilirubin in the bloodstream (hyperbilirubinemia), but this normally has no serious consequences. Mild jaundice may appear under conditions of exertion or stress.