Enhance Potions is an item property commonly found on jewelry. When a potion is used, its effectiveness will increase by the percentage of your cumulative Enhance Potions properties. Healing potions heal more points of damage, curing potions have a better chance to cure poison, etc. There is a total cap of 50%. If your character has the alchemy skill, the cap is raised 10% for every 33 skill points you have. At 99 Alchemy the cap is 80%.
Here is a list of artifacts and other items which have Enhance Potions.
These items are from special events.
The following resources are required to imbue the highest intensity of Enhance Potions (25%):