A complete Sanfew Serum can be used as a weapon against nail beasts, causing significant damage. To use it as a weapon, right-click on the potion and select use, then click on a Nail beast. This should be done if a nail beast is attacking the follower in Temple Trekking. Players cannot use the Assist System to make this potion. Notable uses of Sanfew Serum include K'ril Tsutsaroth and the Dagannoth Kings due to their ability to save space on antipoison potions.