Mice that have been given morphine are very likely to develop blood poisoning because bacteria that normally reside in the intestine typically respond to morphine by migrating into the bloodstream  However, when mice are given both morphine and the new drug naltrexone, blood poisoning is much less frequent, although it does still occur
These results provide support for researchers' prediction that naltrexone will turn out to be toxic to certain types of bacteria
Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream.