In the fourth episode of “Baby Reindeer,” Darrien gives Donny the drug GHB, leaving viewers wondering what it is. GHB, also known as gamma-Hydroxybutyric acid, is prescribed for narcolepsy but can have euphoric effects similar to alcohol and MDMA when abused. Its sedative effects include nausea, dizziness, drowsiness, unconsciousness, and possibly death. Due to its odorless, tasteless, and colorless nature, GHB is often used as a date-rape drug and has a short half-life, making it difficult to detect after an incident.