Should I trust the numbers on this page?

Not as exact figures yet. Each effect is described in plain language and will be checked against the game's own data before we quote numbers.

How do I use this index during a run?

Scan it to recall what an item tends to do. Treat the wording as a description of behaviour, not a verified stat line.

What does each item do in Binding of Isaac?

This index describes each effect in plain language. Treat an entry as behaviour, not a verified stat line.

Which Binding of Isaac items are worth taking?

Items that raise damage or safety without setup. A replacement needs a plan before you commit.

The Binding of Isaac Item Index — Plain-Language Effects

How to read this index

This page lists notable passive and active items with plain-language effects. Numbers are described, not quoted, until we verify them against the game’s own data.

Use it to scan what an item might do before a run. Treat every entry here as a description, not a promise.

Item	Type	Effect (plain language)
Brimstone	Passive	Replaces your tears with a charged blood laser. It fires slowly but cuts through a whole line of enemies.
Mom’s Knife	Passive	Replaces your tears with a thrown knife. Heavy on contact, and it returns to you after each throw.
The D6	Active	Rerolls the items on a pedestal or in a room. A weak floor becomes a second chance to find something better.
Epic Fetus	Passive	Replaces your tears with aimed missiles. Enormous damage, but your shots move where you point a marker.
Dr. Fetus	Passive	Fires bombs instead of tears. High damage with a risk of hurting yourself at close range.
Ipecac	Passive	Lobbed explosive tears with high damage. They arc and burst, so point-blank shots can hurt you.
Technology	Passive	Turns your tears into a piercing laser beam. The beam travels in a straight line through enemies.
Spoon Bender	Passive	Gives your tears homing. Shots curve toward enemies, which helps against small or fast targets.
Cupid’s Arrow	Passive	Makes your tears pierce. Each shot passes through an enemy and can hit the next one behind it.
Polyphemus	Passive	Turns your shot into fewer, larger tears. A heavy hit trades fire rate for raw damage.
Sacred Heart	Passive	Homing tears with a large damage boost. Shots rarely miss once you hold it.
Godhead	Passive	Homing tears that damage enemies around them. A strong all-rounder for a late run.
Cricket’s Head	Passive	A damage multiplier plus a flat damage boost. A common way to start a damage build.
Magic Mushroom	Passive	Raises most stats a little and makes you taller. A broad, safe upgrade for any build.
Halo	Passive	Raises a spread of stats together. A well-rounded pickup with no clear downside.
The Mark	Passive	Adds damage and a small speed boost. A plain offense item with a light extra.
Blood of the Martyr	Passive	A flat damage boost that stacks with other items. Simple added power.
Pentagram	Passive	A damage boost with better Devil room odds. A small buff that keeps the deal chance alive.
The Sad Onion	Passive	Raises your tear rate. A plain, reliable speed-up for your shots.
Number One	Passive	Raises tear rate but shortens range. Fast tears that fall short of distant enemies.
Soy Milk	Passive	Fires a rapid stream of weak tears. Enormous rate at the cost of damage per hit.
20/20	Passive	Splits your shot into two streams. More coverage from a single tear.
Inner Eye	Passive	Fires three tears in a fan at a slower rate. Wide coverage for a slower shot.
Mutant Spider	Passive	Fires four tears in a spread at a slow rate. Great coverage, slow fire.
Cricket’s Body	Passive	Splits your tears into smaller shots that scatter on impact. Good against groups.
Tiny Planet	Passive	Your tears orbit around you instead of flying away. They circle and hit nearby enemies.
Ludovico Technique	Passive	Your tear becomes one large shot you steer. You control where it goes for as long as it lives.
The Wafer	Passive	Cuts damage that reaches your health to a sliver. It turns a heavy hit into a small one.
Dead Cat	Passive	Grants nine lives at the cost of your heart containers. A death becomes a reset at low health.
Abaddon	Passive	Trades heart containers for black hearts and a damage boost. Risky, but strong on offense.
Guppy’s Head	Active	Spawns friendly flies that chase enemies. Good for clearing a crowded room.
Guppy’s Tail	Passive	Raises the chance and quality of chests. A luck item tied to the Guppy set.
Book of Belial	Active	Raises your damage for the room and improves Devil room odds. A small buff with a reward.
Blank Card	Active	Makes your next card or rune fire twice. It doubles the value of one good card.
Stop Watch	Passive	Slows enemies after a short time in a room. Slower enemies are easier to dodge.
Mom’s Purse	Passive	Lets you carry an extra trinket. One more small bonus in a spare slot.
Sack Head	Passive	Improves the drops you find. More resources and better chests over a run.
Humbling Bundle	Passive	Turns some single pickups into doubles. More coins, bombs and keys across a floor.
PHD	Passive	Improves pills and turns bad pills good. It also reveals what each pill does.
The Battery	Passive	Lets your active item charge an extra use. More uses from the same slot.
Chaos	Passive	Mixes pickup pools from every room type. Unpredictable, but it can surface rare items.

Back to the Binding of Isaac hub. Related reading: Item synergies basics and Damage versus tears.