Rats' Inability to Vomit Leads to Unusual Outcome.

Rats, mice, and other rodents can't vomit due to a barrier between their stomach and esophagus, and their strong memory for sickening substances. This has resulted in millions of dollars wasted on drug testing, as they can't reveal whether vomiting is a side effect. Researchers are turning to shrews, a rodent-like mammal that can vomit, as an alternative for lab testing.