diff --git a/data/abilities.ts b/data/abilities.ts
index 6feb2f2439..3c86fe588d 100644
--- a/data/abilities.ts
+++ b/data/abilities.ts
@@ -740,33 +740,29 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 		num: 238,
 	},
 	cudchew: {
-		onEatItem(item, pokemon) {
-			if (item.isBerry && pokemon.addVolatile('cudchew')) {
-				pokemon.volatiles['cudchew'].berry = item;
+		onEatItem(item, pokemon, source, effect) {
+			if (item.isBerry && (!effect || !['bugbite', 'pluck'].includes(effect.id))) {
+				this.effectState.berry = item;
+				this.effectState.counter = 2;
+				// This is needed in case the berry was eaten during residuals, preventing the timer from decreasing this turn
+				if (!this.queue.peek()) this.effectState.counter--;
 			}
 		},
-		onEnd(pokemon) {
-			delete pokemon.volatiles['cudchew'];
-		},
-		condition: {
-			noCopy: true,
-			duration: 2,
-			onRestart() {
-				this.effectState.duration = 2;
-			},
-			onResidualOrder: 28,
-			onResidualSubOrder: 2,
-			onEnd(pokemon) {
-				if (pokemon.hp) {
-					const item = this.effectState.berry;
-					this.add('-activate', pokemon, 'ability: Cud Chew');
-					this.add('-enditem', pokemon, item.name, '[eat]');
-					if (this.singleEvent('Eat', item, null, pokemon, null, null)) {
-						this.runEvent('EatItem', pokemon, null, null, item);
-					}
-					if (item.onEat) pokemon.ateBerry = true;
+		onResidualOrder: 28,
+		onResidualSubOrder: 2,
+		onResidual(pokemon) {
+			if (!this.effectState.berry || !pokemon.hp) return;
+			if (--this.effectState.counter <= 0) {
+				const item = this.effectState.berry;
+				this.add('-activate', pokemon, 'ability: Cud Chew');
+				this.add('-enditem', pokemon, item.name, '[eat]');
+				if (this.singleEvent('Eat', item, null, pokemon, null, null)) {
+					this.runEvent('EatItem', pokemon, null, null, item);
 				}
-			},
+				if (item.onEat) pokemon.ateBerry = true;
+				delete this.effectState.berry;
+				delete this.effectState.counter;
+			}
 		},
 		flags: {},
 		name: "Cud Chew",
@@ -4233,34 +4229,30 @@ export const Abilities: import('../sim/dex-abilities').AbilityDataTable = {
 	},
 	slowstart: {
 		onStart(pokemon) {
-			pokemon.addVolatile('slowstart');
+			this.add('-start', pokemon, 'ability: Slow Start');
+			this.effectState.counter = 5;
 		},
-		onEnd(pokemon) {
-			delete pokemon.volatiles['slowstart'];
-			this.add('-end', pokemon, 'Slow Start', '[silent]');
-		},
-		condition: {
-			duration: 5,
-			onResidualOrder: 28,
-			onResidualSubOrder: 2,
-			onStart(target) {
-				this.add('-start', target, 'ability: Slow Start');
-			},
-			onResidual(pokemon) {
-				if (!pokemon.activeTurns) {
-					this.effectState.duration! += 1;
+		onResidualOrder: 28,
+		onResidualSubOrder: 2,
+		onResidual(pokemon) {
+			if (pokemon.activeTurns && this.effectState.counter) {
+				this.effectState.counter--;
+				if (!this.effectState.counter) {
+					this.add('-end', pokemon, 'Slow Start');
+					delete this.effectState.counter;
 				}
-			},
-			onModifyAtkPriority: 5,
-			onModifyAtk(atk, pokemon) {
+			}
+		},
+		onModifyAtkPriority: 5,
+		onModifyAtk(atk, pokemon) {
+			if (this.effectState.counter) {
 				return this.chainModify(0.5);
-			},
-			onModifySpe(spe, pokemon) {
+			}
+		},
+		onModifySpe(spe, pokemon) {
+			if (this.effectState.counter) {
 				return this.chainModify(0.5);
-			},
-			onEnd(target) {
-				this.add('-end', target, 'Slow Start');
-			},
+			}
 		},
 		flags: {},
 		name: "Slow Start",
diff --git a/data/mods/gen4/moves.ts b/data/mods/gen4/moves.ts
index 3e90ffd0c6..f8fb631d38 100644
--- a/data/mods/gen4/moves.ts
+++ b/data/mods/gen4/moves.ts
@@ -550,8 +550,8 @@ export const Moves: import('../../../sim/dex-moves').ModdedMoveDataTable = {
 			this.debug(`BP: ${move.basePower}`);
 			if (item.isBerry) {
 				move.onHit = function (foe) {
-					if (this.singleEvent('Eat', item, null, foe, null, null)) {
-						this.runEvent('EatItem', foe, null, null, item);
+					if (this.singleEvent('Eat', item, source.itemState, foe, source, move)) {
+						this.runEvent('EatItem', foe, source, move, item);
 						if (item.id === 'leppaberry') foe.staleness = 'external';
 					}
 					if (item.onEat) foe.ateBerry = true;
diff --git a/data/mods/gen7/abilities.ts b/data/mods/gen7/abilities.ts
index d70cff4602..83905da67e 100644
--- a/data/mods/gen7/abilities.ts
+++ b/data/mods/gen7/abilities.ts
@@ -87,33 +87,18 @@ export const Abilities: import('../../../sim/dex-abilities').ModdedAbilityDataTa
 	},
 	slowstart: {
 		inherit: true,
-		condition: {
-			duration: 5,
-			onResidualOrder: 28,
-			onResidualSubOrder: 2,
-			onStart(target) {
-				this.add('-start', target, 'ability: Slow Start');
-			},
-			onModifyAtkPriority: 5,
-			onModifyAtk(atk, pokemon, target, move) {
-				// This is because the game checks the move's category in data, rather than what it is currently, unlike e.g. Huge Power
-				if (this.dex.moves.get(move.id).category === 'Physical') {
-					return this.chainModify(0.5);
-				}
-			},
-			onModifySpAPriority: 5,
-			onModifySpA(spa, pokemon, target, move) {
-				// Ordinary Z-moves like Breakneck Blitz will halve the user's Special Attack as well
-				if (this.dex.moves.get(move.id).category === 'Physical') {
-					return this.chainModify(0.5);
-				}
-			},
-			onModifySpe(spe, pokemon) {
+		onModifyAtk(atk, pokemon, target, move) {
+			// This is because the game checks the move's category in data, rather than what it is currently, unlike e.g. Huge Power
+			if (this.effectState.counter && this.dex.moves.get(move.id).category === 'Physical') {
 				return this.chainModify(0.5);
-			},
-			onEnd(target) {
-				this.add('-end', target, 'Slow Start');
-			},
+			}
+		},
+		onModifySpAPriority: 5,
+		onModifySpA(spa, pokemon, target, move) {
+			// Ordinary Z-moves like Breakneck Blitz will halve the user's Special Attack as well
+			if (this.effectState.counter && this.dex.moves.get(move.id).category === 'Physical') {
+				return this.chainModify(0.5);
+			}
 		},
 	},
 	soundproof: {
diff --git a/data/moves.ts b/data/moves.ts
index 78ad165459..8f26c3e7ee 100644
--- a/data/moves.ts
+++ b/data/moves.ts
@@ -1982,12 +1982,12 @@ export const Moves: import('../sim/dex-moves').MoveDataTable = {
 		pp: 20,
 		priority: 0,
 		flags: { contact: 1, protect: 1, mirror: 1, metronome: 1 },
-		onHit(target, source) {
+		onHit(target, source, move) {
 			const item = target.getItem();
 			if (source.hp && item.isBerry && target.takeItem(source)) {
 				this.add('-enditem', target, item.name, '[from] stealeat', '[move] Bug Bite', `[of] ${source}`);
-				if (this.singleEvent('Eat', item, null, source, null, null)) {
-					this.runEvent('EatItem', source, null, null, item);
+				if (this.singleEvent('Eat', item, target.itemState, source, source, move)) {
+					this.runEvent('EatItem', source, source, move, item);
 					if (item.id === 'leppaberry') target.staleness = 'external';
 				}
 				if (item.onEat) source.ateBerry = true;
@@ -5950,9 +5950,12 @@ export const Moves: import('../sim/dex-moves').MoveDataTable = {
 			move.basePower = item.fling.basePower;
 			this.debug(`BP: ${move.basePower}`);
 			if (item.isBerry) {
+				if (source.hasAbility('cudchew')) {
+					this.singleEvent('EatItem', source.getAbility(), source.abilityState, source, source, move, item);
+				}
 				move.onHit = function (foe) {
-					if (this.singleEvent('Eat', item, null, foe, null, null)) {
-						this.runEvent('EatItem', foe, null, null, item);
+					if (this.singleEvent('Eat', item, source.itemState, foe, source, move)) {
+						this.runEvent('EatItem', foe, source, move, item);
 						if (item.id === 'leppaberry') foe.staleness = 'external';
 					}
 					if (item.onEat) foe.ateBerry = true;
@@ -13918,12 +13921,12 @@ export const Moves: import('../sim/dex-moves').MoveDataTable = {
 		pp: 20,
 		priority: 0,
 		flags: { contact: 1, protect: 1, mirror: 1, distance: 1, metronome: 1 },
-		onHit(target, source) {
+		onHit(target, source, move) {
 			const item = target.getItem();
 			if (source.hp && item.isBerry && target.takeItem(source)) {
 				this.add('-enditem', target, item.name, '[from] stealeat', '[move] Pluck', `[of] ${source}`);
-				if (this.singleEvent('Eat', item, null, source, null, null)) {
-					this.runEvent('EatItem', source, null, null, item);
+				if (this.singleEvent('Eat', item, target.itemState, source, source, move)) {
+					this.runEvent('EatItem', source, source, move, item);
 					if (item.id === 'leppaberry') target.staleness = 'external';
 				}
 				if (item.onEat) source.ateBerry = true;
diff --git a/sim/dex-conditions.ts b/sim/dex-conditions.ts
index dd58a299f9..990ce7cd93 100644
--- a/sim/dex-conditions.ts
+++ b/sim/dex-conditions.ts
@@ -48,7 +48,7 @@ export interface EventMethods {
 	onDeductPP?: (this: Battle, target: Pokemon, source: Pokemon) => number | void;
 	onDisableMove?: (this: Battle, pokemon: Pokemon) => void;
 	onDragOut?: (this: Battle, pokemon: Pokemon, source?: Pokemon, move?: ActiveMove) => void;
-	onEatItem?: (this: Battle, item: Item, pokemon: Pokemon) => void;
+	onEatItem?: (this: Battle, item: Item, pokemon: Pokemon, source?: Pokemon, effect?: Effect) => void;
 	onEffectiveness?: MoveEventMethods['onEffectiveness'];
 	onEntryHazard?: (this: Battle, pokemon: Pokemon) => void;
 	onFaint?: CommonHandlers['VoidEffect'];
diff --git a/sim/pokemon.ts b/sim/pokemon.ts
index d1fe3d5b63..47d4b2d727 100644
--- a/sim/pokemon.ts
+++ b/sim/pokemon.ts
@@ -1751,7 +1751,7 @@ export class Pokemon {
 			this.battle.add('-enditem', this, item, '[eat]');
 
 			this.battle.singleEvent('Eat', item, this.itemState, this, source, sourceEffect);
-			this.battle.runEvent('EatItem', this, null, null, item);
+			this.battle.runEvent('EatItem', this, source, sourceEffect, item);
 
 			if (RESTORATIVE_BERRIES.has(item.id)) {
 				switch (this.pendingStaleness) {
diff --git a/test/sim/abilities/cudchew.js b/test/sim/abilities/cudchew.js
new file mode 100644
index 0000000000..f04630c69b
--- /dev/null
+++ b/test/sim/abilities/cudchew.js
@@ -0,0 +1,91 @@
+'use strict';
+
+const assert = require('./../../assert');
+const common = require('./../../common');
+
+let battle;
+
+describe('Cud Chew', () => {
+	afterEach(() => {
+		battle.destroy();
+	});
+
+	it(`should re-activate a berry, eaten in the previous turn`, () => {
+		battle = common.createBattle([[
+			{ species: 'tauros', ability: 'cudchew', item: 'lumberry', moves: ['sleeptalk'] },
+		], [
+			{ species: 'toxicroak', moves: ['toxic'] },
+		]]);
+		const tauros = battle.p1.active[0];
+		battle.makeChoices();
+		assert.equal(tauros.status, '');
+		battle.makeChoices();
+		assert.equal(tauros.status, '');
+		battle.makeChoices();
+		assert.equal(tauros.status, 'tox');
+	});
+
+	it(`should re-activate a berry flung in the previous turn, for both the attacker and the target`, () => {
+		battle = common.createBattle({ gameType: 'doubles' }, [[
+			{ species: 'tauros', ability: 'cudchew', item: 'lumberry', moves: ['fling', 'sleeptalk'] },
+			{ species: 'foongus', moves: ['toxic', 'sleeptalk'] },
+		], [
+			{ species: 'farigiraf', ability: 'cudchew', moves: ['sleeptalk'] },
+			{ species: 'grimer', moves: ['toxic', 'sleeptalk'] },
+		]]);
+		const tauros = battle.p1.active[0];
+		const farigiraf = battle.p2.active[0];
+		battle.makeChoices('move fling 1, move toxic 1', 'move sleeptalk, move toxic 1');
+		assert.equal(tauros.status, 'tox');
+		assert.equal(farigiraf.status, 'tox');
+		battle.makeChoices('move sleeptalk, move sleeptalk', 'move sleeptalk, move sleeptalk');
+		assert.equal(tauros.status, '');
+		assert.equal(farigiraf.status, '');
+	});
+
+	it(`should not re-activate a berry eaten by Bug Bite, for either the attacker or the target`, () => {
+		battle = common.createBattle({ gameType: 'doubles' }, [[
+			{ species: 'tauros', ability: 'cudchew', moves: ['bugbite', 'sleeptalk'] },
+			{ species: 'foongus', moves: ['toxic', 'sleeptalk'] },
+		], [
+			{ species: 'farigiraf', ability: 'cudchew', item: 'lumberry', moves: ['sleeptalk'] },
+			{ species: 'grimer', moves: ['toxic', 'sleeptalk'] },
+		]]);
+		const tauros = battle.p1.active[0];
+		const farigiraf = battle.p2.active[0];
+		battle.makeChoices('move bugbite 1, move toxic 1', 'move sleeptalk, move toxic 1');
+		assert.equal(tauros.status, 'tox');
+		assert.equal(farigiraf.status, 'tox');
+		battle.makeChoices('move sleeptalk, move sleeptalk', 'move sleeptalk, move sleeptalk');
+		assert.equal(tauros.status, 'tox');
+		assert.equal(farigiraf.status, 'tox');
+	});
+
+	it(`should not be prevented by Unnerve`, () => {
+		battle = common.createBattle({ gameType: 'doubles' }, [[
+			{ species: 'tauros', ability: 'cudchew', item: 'lumberry', moves: ['sleeptalk'] },
+			{ species: 'wynaut', moves: ['sleeptalk'] },
+		], [
+			{ species: 'toxicroak', moves: ['toxic'] },
+			{ species: 'magikarp', moves: ['sleeptalk'] },
+			{ species: 'mewtwo', ability: 'unnerve', moves: ['sleeptalk'] },
+		]]);
+		const tauros = battle.p1.active[0];
+		battle.makeChoices();
+		assert.equal(tauros.status, '');
+		battle.makeChoices('auto', 'move toxic 1, switch 3');
+		assert.equal(tauros.status, '');
+	});
+
+	it(`should still activate in the following turn if the berry was consumed during residuals`, () => {
+		battle = common.createBattle([[
+			{ species: 'tauros', ability: 'cudchew', item: 'sitrusberry', moves: ['bellydrum'] },
+		], [
+			{ species: 'toxicroak', moves: ['toxic'] },
+		]]);
+		const tauros = battle.p1.active[0];
+		battle.makeChoices();
+		battle.makeChoices();
+		assert(tauros.hp > tauros.maxhp * 3 / 4, 'Tauros should have eaten its berry twice');
+	});
+});
diff --git a/test/sim/abilities/neutralizinggas.js b/test/sim/abilities/neutralizinggas.js
index b3f543844c..9aff3055a4 100644
--- a/test/sim/abilities/neutralizinggas.js
+++ b/test/sim/abilities/neutralizinggas.js
@@ -274,6 +274,43 @@ describe('Neutralizing Gas', () => {
 		assert.species(eiscue, 'Eiscue-Noice');
 	});
 
+	it(`should delay the activation of Cud Chew`, () => {
+		battle = common.createBattle({ gameType: 'doubles' }, [[
+			{ species: 'tauros', ability: 'cudchew', item: 'lumberry', moves: ['sleeptalk'] },
+			{ species: 'wynaut', moves: ['sleeptalk'] },
+		], [
+			{ species: 'toxicroak', moves: ['toxic'] },
+			{ species: 'magikarp', moves: ['sleeptalk'] },
+			{ species: 'weezing', ability: 'neutralizinggas', moves: ['sleeptalk'] },
+		]]);
+		let tauros = battle.p1.active[0];
+		battle.makeChoices();
+		assert.equal(tauros.status, '');
+		battle.makeChoices('auto', 'move toxic 1, switch 3');
+		assert.equal(tauros.status, 'tox');
+		battle.makeChoices('auto', 'move toxic 1, switch 3');
+		assert.equal(tauros.status, '');
+
+		battle = common.createBattle({ gameType: 'doubles' }, [[
+			{ species: 'tauros', ability: 'cudchew', item: 'lumberry', moves: ['sleeptalk'] },
+			{ species: 'wynaut', moves: ['sleeptalk'] },
+		], [
+			{ species: 'toxicroak', moves: ['toxic'] },
+			{ species: 'magikarp', moves: ['sleeptalk', 'uturn'] },
+			{ species: 'weezing', ability: 'neutralizinggas', moves: ['sleeptalk'] },
+		]]);
+		tauros = battle.p1.active[0];
+		battle.makeChoices('auto', 'move toxic 1, move uturn 2');
+		battle.makeChoices();
+		assert.equal(tauros.status, ''); // 0 turns passed before Neutralizing Gas
+		battle.makeChoices();
+		assert.equal(tauros.status, 'tox');
+		battle.makeChoices('auto', 'move toxic 1, switch 3');
+		assert.equal(tauros.status, 'tox'); // 1 turn has passed
+		battle.makeChoices();
+		assert.equal(tauros.status, '');
+	});
+
 	it(`should not work if it was obtained via Transform`, () => {
 		battle = common.createBattle([[
 			{ species: 'Ditto', moves: ['transform'] },