One of the best parts of the Binding of Isaac is the huge number of item interactions and synergies you can get by combining certain items, however they don't always work as expected.
This page documents some of the more noteworthy item synergies available. Just select an item from each of the two selection boxes below to see a description of their in-game synergy.
*NOTE*: This page has synergies for the original game, for Rebirth & Afterbirth synergies click here
The colour coding is there to give you an idea of which synergies work as expected and which ones can affect you negatively.
• A red square means that the selected combination of items is actively harmful to your stats and would be better off without one of the items.
• Orange means the synergy doesn't work as expected but is neither positive or negative and it can also mean that one item simply overrides another.
• A green synergy means both items compliment each other and work as you would expect!