- "This is the best thing to take when you get poisoned."
- — In-game Description
Vial of Serum (Japanese: けっせい Serum) is a medicine item in Earthbound which works as an antidote for the poison status ailment on party members. It can be purchased in Scaraba (Hassan's Shop and Red Snake's Shop) and Threed (Drugstore ) for $58.00.
Vial of Serum can be dropped by Skelpions in Dusty Dunes Desert, and although it is quite rare it is convenient as Skelpions have a high rate of poisoning party members. It is the only known medicine in Earthbound to primarily cure poison, making it equivalent to the Antidote in Mother and Mother 3.
The only other items that cure poison are Secret Herb, Refreshing Herb, Cup of Life Noodles and Horn of Life. Other methods include visiting a doctor at a hospital, resting at a hotel or PSI Healing β and higher.
- This item is likely intended to be an antivenom that is acquired from extracting the poison from the stingers of Skelpions, this would explain how the only way of acquiring it without purchasing it is from Skelpions.