Twenty-six cases of people in the 1990s who died unexpectedly while in police custody after being doused with pepper spray might be explained by a toxic reaction caused by capsaicin in the spray. It seems that pepper spray intensifies the effect of cocaine and other psychostimulants, resulting in death. All the victims had either cocaine or another psychostimulant in their bloodstreams. Laboratory tests on mice support the evidence that mixing capsaicin and cocaine makes for a very bad high. Read more here.