diff --git a/src/Spout/Common/Helper/GlobalFunctionsHelper.php b/src/Spout/Common/Helper/GlobalFunctionsHelper.php
index 1d660c1..dd4356e 100644
--- a/src/Spout/Common/Helper/GlobalFunctionsHelper.php
+++ b/src/Spout/Common/Helper/GlobalFunctionsHelper.php
@@ -252,6 +252,17 @@ class GlobalFunctionsHelper
         header($string);
     }
 
+    /**
+     * Wrapper around global function ob_end_clean()
+     * @see ob_end_clean()
+     *
+     * @return void
+     */
+    public function ob_end_clean()
+    {
+        ob_end_clean();
+    }
+
     /**
      * Wrapper around global function iconv()
      * @see iconv()
diff --git a/src/Spout/Writer/AbstractWriter.php b/src/Spout/Writer/AbstractWriter.php
index e5f9ad7..46f47cc 100644
--- a/src/Spout/Writer/AbstractWriter.php
+++ b/src/Spout/Writer/AbstractWriter.php
@@ -121,6 +121,10 @@ abstract class AbstractWriter implements WriterInterface
         $this->filePointer = $this->globalFunctionsHelper->fopen('php://output', 'w');
         $this->throwIfFilePointerIsNotAvailable();
 
+        // Clear any previous output (otherwise the generated file will be corrupted)
+        // @see https://github.com/box/spout/issues/241
+        $this->globalFunctionsHelper->ob_end_clean();
+
         // Set headers
         $this->globalFunctionsHelper->header('Content-Type: ' . static::$headerContentType);
         $this->globalFunctionsHelper->header('Content-Disposition: attachment; filename="' . $this->outputFilePath . '"');