Serum 207

Serum 207 is a potion that can be made after reading the diary of Herbi Flax during the Shades of Mort'ton quest, by adding ashes to a tarromin potion (unf), requiring level 15 Herblore and yielding 50 Herblore experience. It can be used to temporarily cure the otherwise incoherent, afflicted villagers of Mort'ton in exchange for a reward, as part of the Shades of Mort'ton minigame. It can also be used on the lit fire altar inside the Mort'ton temple, requiring 20% sanctity, to turn it into serum 208, which can be used to cure the afflicted in return for better rewards.

As the possible rewards for curing the afflicted include all the items required to make the potion, and the only other potions that can be made with tarromin are strength potions, which give the same experience but require limpwurt root to make, making serum 207 can be used as an inexpensive, albeit slow, method of training Herblore.

Unlike other potions, the process of creating serum 207 doesn't have make-x option; instead, the player will keep creating them automatically until they run out of supplies. Additionally, the prescription goggles, amulet of chemistry, and alchemist's amulet have no effect when making this potion, and ashes stored in the reagent pouch will not be used.

• The name of serum 207 comes from the "solution content value" of the ingredients shown on the last page of Herbi Flax's diary: water (100), tarromin (94), and ashes (13) sum to 207.