diff --git a/src/Captcha/TextCaptcha.php b/src/Captcha/TextCaptcha.php
index c3b24af81..1a27afeb9 100644
--- a/src/Captcha/TextCaptcha.php
+++ b/src/Captcha/TextCaptcha.php
@@ -34,6 +34,7 @@ class TextCaptcha implements CaptchaInterface
      */
     public function __construct(array $settings)
     {
+        session_unset();
         session_start();
 
         $this->settings = $settings;