diff --git a/5etools-docker/Dockerfile b/5etools-docker/Dockerfile
index 42130195..c5c0c14f 100644
--- a/5etools-docker/Dockerfile
+++ b/5etools-docker/Dockerfile
@@ -7,5 +7,5 @@ apt-get -y install curl p7zip-full
 WORKDIR /usr/local/apache2/htdocs/
 RUN mkdir download
 ENV IMG false
-HEALTHCHECK --startperiod=1m CMD /healthcheck.sh 
+HEALTHCHECK --start-period=1m CMD /healthcheck.sh 
 CMD ["/bin/bash","/init.sh"]
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