diff --git a/src/Entities/Item.php b/src/Entities/Item.php
index 8e7b226..aba875d 100644
--- a/src/Entities/Item.php
+++ b/src/Entities/Item.php
@@ -20,6 +20,7 @@ use AtolOnline\{
     Exceptions\InvalidDeclarationNumberException,
     Exceptions\InvalidEnumValueException,
     Exceptions\InvalidOKSMCodeException,
+    Exceptions\NegativeItemExciseException,
     Exceptions\NegativeItemPriceException,
     Exceptions\NegativeItemQuantityException,
     Exceptions\TooHighItemQuantityException,
@@ -28,7 +29,8 @@ use AtolOnline\{
     Exceptions\TooLongItemNameException,
     Exceptions\TooLongMeasurementUnitException,
     Exceptions\TooLongUserdataException,
-    Exceptions\TooManyException};
+    Exceptions\TooManyException
+};
 
 /**
  * Предмет расчёта (товар, услуга)
@@ -92,6 +94,11 @@ class Item extends Entity
      */
     protected ?string $user_data = null;
 
+    /**
+     * @var float|null Сумма акциза, включенная в стоимость (1229)
+     */
+    protected ?float $excise = null;
+
     /**
      * @var string|null Цифровой код страны происхождения товара (1230)
      */
@@ -214,14 +221,14 @@ class Item extends Entity
     }
 
     /**
-     * Возвращает стоимость
+     * Возвращает стоимость (цена * количество + акциз)
      *
      * @return float
      * @throws TooHighSumException
      */
     public function getSum(): float
     {
-        $sum = $this->price * $this->quantity;
+        $sum = $this->getPrice() * $this->getQuantity() + (float)$this->getExcise();
         if ($sum > Constraints::MAX_COUNT_ITEM_PRICE) {
             throw new TooHighSumException($this->getName(), $sum);
         }
@@ -321,16 +328,19 @@ class Item extends Entity
      * @param Vat|string|null $vat Объект ставки, одно из значений VatTypes или null для удаления ставки
      * @return $this
      * @throws TooHighSumException
+     * @throws InvalidEnumValueException
      */
     public function setVat(Vat|string|null $vat): self
     {
         if (is_string($vat)) {
             $vat = trim($vat);
-            VatTypes::isValid($vat) && $vat = new Vat($vat, $this->getSum());
+            empty($vat)
+                ? $this->vat = null
+                : VatTypes::isValid($vat) && $this->vat = new Vat($vat, $this->getSum());
         } elseif ($vat instanceof Vat) {
             $vat->setSum($this->getSum());
+            $this->vat = $vat;
         }
-        $this->vat = $vat ?: null;
         return $this;
     }
 
@@ -405,6 +415,32 @@ class Item extends Entity
         return $this;
     }
 
+    /**
+     * Возвращает установленную сумму акциза
+     *
+     * @return float|null
+     */
+    public function getExcise(): ?float
+    {
+        return $this->excise;
+    }
+
+    /**
+     * Устанавливает сумму акциза
+     *
+     * @param float|null $excise
+     * @return Item
+     * @throws NegativeItemExciseException
+     */
+    public function setExcise(?float $excise): Item
+    {
+        if ($excise < 0) {
+            throw new NegativeItemExciseException($this->getName(), $excise);
+        }
+        $this->excise = $excise;
+        return $this;
+    }
+
     /**
      * Возвращает установленный код страны происхождения товара
      *
@@ -499,16 +535,16 @@ class Item extends Entity
             'quantity' => $this->getQuantity(),
             'sum' => $this->getSum(),
         ];
-        $this->getMeasurementUnit() && $json['measurement_unit'] = $this->getMeasurementUnit();
-        $this->getPaymentMethod() && $json['payment_method'] = $this->getPaymentMethod();
-        $this->getPaymentObject() && $json['payment_object'] = $this->getPaymentObject();
-        $this->getDeclarationNumber() && $json['declaration_number'] = $this->getDeclarationNumber();
+        !is_null($this->getMeasurementUnit()) && $json['measurement_unit'] = $this->getMeasurementUnit();
+        !is_null($this->getPaymentMethod()) && $json['payment_method'] = $this->getPaymentMethod();
+        !is_null($this->getPaymentObject()) && $json['payment_object'] = $this->getPaymentObject();
+        !is_null($this->getDeclarationNumber()) && $json['declaration_number'] = $this->getDeclarationNumber();
         $this->getVat()?->jsonSerialize() && $json['vat'] = $this->getVat()->jsonSerialize();
         $this->getAgentInfo()?->jsonSerialize() && $json['agent_info'] = $this->getAgentInfo()->jsonSerialize();
         $this->getSupplier()?->jsonSerialize() && $json['supplier_info'] = $this->getSupplier()->jsonSerialize();
-        $this->getUserData() && $json['user_data'] = $this->getUserData();
-        //TODO excise
-        $this->getCountryCode() && $json['country_code'] = $this->getCountryCode();
+        !is_null($this->getUserData()) && $json['user_data'] = $this->getUserData();
+        !is_null($this->getExcise()) && $json['excise'] = $this->getExcise();
+        !is_null($this->getCountryCode()) && $json['country_code'] = $this->getCountryCode();
         //TODO nomenclature_code
         return $json;
     }
diff --git a/src/Exceptions/NegativeItemExciseException.php b/src/Exceptions/NegativeItemExciseException.php
new file mode 100644
index 0000000..4642a75
--- /dev/null
+++ b/src/Exceptions/NegativeItemExciseException.php
@@ -0,0 +1,33 @@
+<?php
+/*
+ * Copyright (c) 2020-2021 Антон Аксенов (Anthony Axenov)
+ *
+ * This code is licensed under MIT.
+ * Этот код распространяется по лицензии MIT.
+ * https://github.com/anthonyaxenov/atol-online/blob/master/LICENSE
+ */
+
+declare(strict_types = 1);
+
+namespace AtolOnline\Exceptions;
+
+use AtolOnline\Constants\Ffd105Tags;
+
+/**
+ * Исключение, возникающее при попытке указать предмету расчёта отрицательный акциз
+ */
+class NegativeItemExciseException extends AtolException
+{
+    protected array $ffd_tags = [Ffd105Tags::ITEM_EXCISE];
+
+    /**
+     * Конструктор
+     *
+     * @param string $name
+     * @param float $excise
+     */
+    public function __construct(string $name, float $excise)
+    {
+        parent::__construct("Предмет расчёта '$name' не может иметь отрицательный акциз $excise");
+    }
+}
diff --git a/tests/AtolOnline/Tests/Entities/ItemTest.php b/tests/AtolOnline/Tests/Entities/ItemTest.php
index 4de59d0..9ac45ce 100644
--- a/tests/AtolOnline/Tests/Entities/ItemTest.php
+++ b/tests/AtolOnline/Tests/Entities/ItemTest.php
@@ -28,6 +28,7 @@ use AtolOnline\{
     Exceptions\InvalidInnLengthException,
     Exceptions\InvalidOKSMCodeException,
     Exceptions\InvalidPhoneException,
+    Exceptions\NegativeItemExciseException,
     Exceptions\NegativeItemPriceException,
     Exceptions\NegativeItemQuantityException,
     Exceptions\TooHighItemQuantityException,
@@ -390,15 +391,16 @@ class ItemTest extends BasicTestCase
      *
      * @param mixed $vat
      * @dataProvider providerNullableStrings
-     * @covers \AtolOnline\Entities\Item::setVat
-     * @covers \AtolOnline\Entities\Item::getVat
-     * @covers \AtolOnline\Entities\Item::jsonSerialize
+     * @covers       \AtolOnline\Entities\Item::setVat
+     * @covers       \AtolOnline\Entities\Item::getVat
+     * @covers       \AtolOnline\Entities\Item::jsonSerialize
      * @throws EmptyItemNameException
      * @throws NegativeItemPriceException
      * @throws NegativeItemQuantityException
      * @throws TooHighPriceException
      * @throws TooLongItemNameException
      * @throws TooManyException
+     * @throws InvalidEnumValueException
      */
     public function testNullableVatByString(mixed $vat): void
     {
@@ -656,4 +658,52 @@ class ItemTest extends BasicTestCase
         (new Item('test item', 2, 3))
             ->setDeclarationNumber(Helpers::randomStr(Constraints::MAX_LENGTH_DECLARATION_NUMBER + 1));
     }
+
+    /**
+     * Тестирует установку акциза и расчёт суммы с его учётом
+     *
+     * @covers \AtolOnline\Entities\Item::setExcise
+     * @covers \AtolOnline\Entities\Item::getExcise
+     * @covers \AtolOnline\Entities\Item::getSum
+     * @covers \AtolOnline\Entities\Item::jsonSerialize
+     * @throws TooLongItemNameException
+     * @throws TooHighPriceException
+     * @throws TooManyException
+     * @throws NegativeItemPriceException
+     * @throws EmptyItemNameException
+     * @throws NegativeItemQuantityException
+     * @throws NegativeItemExciseException
+     */
+    public function testExcise(): void
+    {
+        $this->assertAtolable(
+            (new Item('test item', 2, 3))->setExcise(1),
+            [
+                'name' => 'test item',
+                'price' => 2,
+                'quantity' => 3,
+                'sum' => 7,
+                'excise' => 1,
+            ]
+        );
+    }
+
+    /**
+     * Тестирует установку акциза и расчёт суммы с его учётом
+     *
+     * @covers \AtolOnline\Entities\Item::setExcise
+     * @covers \AtolOnline\Exceptions\NegativeItemExciseException
+     * @throws TooLongItemNameException
+     * @throws TooHighPriceException
+     * @throws TooManyException
+     * @throws NegativeItemPriceException
+     * @throws EmptyItemNameException
+     * @throws NegativeItemQuantityException
+     * @throws NegativeItemExciseException
+     */
+    public function testNegativeItemExciseException(): void
+    {
+        $this->expectException(NegativeItemExciseException::class);
+        (new Item('test item', 2, 3))->setExcise(-1);
+    }
 }