diff --git a/extraction/named_entity/Chemlistem/requirements.txt b/extraction/named_entity/Chemlistem/requirements.txt
index 4b41e184a..2de9c98c9 100644
--- a/extraction/named_entity/Chemlistem/requirements.txt
+++ b/extraction/named_entity/Chemlistem/requirements.txt
@@ -35,7 +35,7 @@ termcolor==1.1.0
 thinc==6.5.2
 toolz==0.9.0
 tqdm==4.31.1
-ujson==1.35
+ujson==5.4.0
 urllib3==1.24.2
 wcwidth==0.1.7
 Werkzeug==0.15.2