Growth serum is a JurassiCraft item that, when given to a prehistoric creature, instantly increases the size and age of said creature. It can only be used on creatures added by JurassiCraft. It is crafted by placing cactus green, a golden carrot, a water bucket, and a food item into the crafting table.
The growth serum can be used at any time on a prehistoric creature from newborn to almost grown. Once fully grown, the creature will not take any more growth serum. The amount of serum needed to grow a creature from infant to adult varies between species.