Wikia

"Your pheromonal attractant was insufficient to bend her to your will; that has never happened before."
"I had noticed that, thank you."
"This failure has made her more appealing."

―Guri and Prince Xizor discuss Xizor's failure to seduce Leia Organa^[src]

Pheromones were chemicals secreted by one lifeform to influence the behavior of other lifeforms, most often to attract members of the opposite sex. Though normally targeting members of the same species, some species such as the Falleen and Zeltrons had unusually powerful pheromones that could affect other sentient races. These two species were also unusual in that they could exude pheromones at will, rather than unconsciously. Bith released pheromones to attract a mate, as they relied on machines to breed. Rodian pheromones were often described as foul-smelling.^[1] Greeata Jendowanian, a Rodian dancer, wore bracelets that would suppress her pheromones.^[2]

The Aing-Tii species communicated through pheromones, and created a device that could analyze their pheromones and translate them into basic, to help them communicate with other species.