diff --git a/server/lemmatizer_resource.py b/server/lemmatizer_resource.py
index 34f9e76..418e5b4 100644
--- a/server/lemmatizer_resource.py
+++ b/server/lemmatizer_resource.py
@@ -35,7 +35,7 @@ class LemmatizerResource(Resource):
         return {'tokens':' '.join(tokens), 'isFirstLemmatized':self.isFirstLemmatized(raw_tokens, language)}
 
     def isFirstLemmatized(self, raw_tokens, language):
-        if language == 'pl':
+        if language == 'pl' and len(raw_tokens) > 0:
             first_token = raw_tokens[0]
             if self.lemmatizeWord(first_token, language) != first_token:
                 return False