diff --git a/src/Types/TypePharmacodeTwoCode.php b/src/Types/TypePharmacodeTwoCode.php
index dca3811..7c1959a 100644
--- a/src/Types/TypePharmacodeTwoCode.php
+++ b/src/Types/TypePharmacodeTwoCode.php
@@ -9,6 +9,7 @@
 
 use Picqer\Barcode\Barcode;
 use Picqer\Barcode\BarcodeBar;
+use Picqer\Barcode\Exceptions\InvalidLengthException;
 
 class TypePharmacodeTwoCode implements TypeInterface
 {
@@ -16,6 +17,10 @@ public function getBarcodeData(string $code): Barcode
     {
         $code = intval($code);
 
+        if ($code < 1) {
+            throw new InvalidLengthException('Pharmacode 2 needs a number of 1 or larger');
+        }
+
         $seq = '';
 
         do {
diff --git a/tests/PharmacodeTest.php b/tests/PharmacodeTest.php
new file mode 100644
index 0000000..c068ffb
--- /dev/null
+++ b/tests/PharmacodeTest.php
@@ -0,0 +1,15 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+class PharmacodeTest extends TestCase
+{
+    public function test_validation_triggerd_when_generating_zero_code()
+    {
+        $pharmacode = new Picqer\Barcode\Types\TypePharmacodeTwoCode();
+
+        $this->expectException(Picqer\Barcode\Exceptions\InvalidLengthException::class);
+
+        $pharmacode->getBarcodeData('0');
+    }
+}