Ginger

Ginger is a root which grows in many places on Earth. Used as a spice by humans, it was found to have a powerful narcotic effect on both males and females of the Race, and to disrupt the hormonal balance of females, causing them to become fertile and emit sexual pheromones which attract males every time they taste it. Despite the Race's best efforts to ban ginger, it is both powerfully addictive for the Race and extremely lucrative to smugglers of every species. (Many human smugglers were secretly encouraged by various Earth governments to disrupt the Race's culture.) Ginger had become firmly entrenched on Home long before the arrival of Tosevites there.