This article is about the cleaned herb. For the grimy herb, see Grimy guam leaf
Guam leaves are the first herbs that a player can clean, with a Herblore level of 3, giving 2.5 Herblore experience. They are used to make attack potions, for fuelling swamp lizards in the form of guam tar, and for making Guthix rest potions, after completing the related segment of the One Small Favour quest. Guam leaves can be grown in a herb patch with a Farming level of 9. To create a potion, you need to add the cleaned herb to a vial of water to create a guam potion (unf), and then add the secondary ingredient.
Guam leaves, along with Marrentills, are used in the Lunar Diplomacy quest to make Guam-marr vials for 84 experience per herb. The vial can then be destroyed and received again from Baba Yaga. Only a short trip to a nearby water source is required. This is a good way of getting rid of guam leaves and marrentill herbs for about 35k experience per hour.
For an exhaustive list of all known sources for this item, see here