Hester Stewart was studying molecular medicine at the University of Sussex
A 26-year-old man has been arrested by police investigating the death of a student linked to the drug GBL.
Sussex Police said the man was arrested on suspicion of intent to supply and bailed pending further inquiries.
Hester Stewart, a 21-year-old medical student from Sussex University, died in Brighton on Sunday.
Officers are investigating whether she unknowingly took GBL during an evening out. The results of toxicology tests are expected in a fortnight's time.
Initial findings in the police inquiry have suggested she died as a result of complications caused by GBL, which can be bought legally in the UK.
Miss Stewart's family are calling on the government to ban the drug which is already proscribed for personal use in several countries.
Her mother, Maryon, has said she will write to Home Secretary Jacqui Smith calling for it to banned.
Earlier this week, she said: "My heart is bleeding for the loss of my dear, beautiful, bright, intelligent daughter and I am too choked to speak."
The Home Office said officials were concerned that its use appeared to be increasing.