Star Trek: 10 Things You Didn't Know About T'Pol
4. It's A Trellium Down For This Storyline
The third season of Enterprise saw T'Pol exposed to a compound that was known as Trellium D. It was highly addictive, and damaging. Its first appearance came in Impulse, which is effectively the Zombie Vulcan episode - a genuinely unnerving story about the Vulcan Science Ship Seleya.
T'Pol's addiction to this substance, using it to expand her understanding of emotions, was a controversial one. Brannon Braga later said that he understood this storyline would be a controversial one, as it would show T'Pol knowingly continuing to abuse the substance to further her own understanding of emotions.
As this was a storyline that had notably never been attempted with any of the male Vulcans in the franchise, it left the door open to criticism as to why exactly the writers were going down this route. Though they would later defend the storyline, it remains a highly controversial one to this day.