Synthetic Marijuana Warning Issued After 'Spice' Leaves Dozens Hospitalized With Severe Bleeding

Synthetic marijuana, also referred to as 'Spice' and 'K2,' is a mixture of shredded plant materials that have been sprayed with man-made, psychoactive chemicals that mimic the euphoric sensation of tetrahydrocannabinol (THC), the primary psychoactive ingredient in cannabis. While the US has banned several mixtures, new formulas continue to emerge.