diff --git a/docs/curl.1 b/docs/curl.1
index 604e77f03936a3467454c0a47d1be39be31e2f7d..01b9cc14a1358e089374bc18a635c172da314968 100644
--- a/docs/curl.1
+++ b/docs/curl.1
@@ -687,6 +687,10 @@ If this option is used several times, the last one will be used.
 Use specified HTTP proxy. If the port number is not specified, it is assumed
 at port 1080.
 
+This option overrides existing environment variables that sets proxy to
+use. If there's an environment variable setting a proxy, you can set proxy to
+"" to override it.
+
 \fBNote\fP that all operations that are performed over a HTTP proxy will
 transparantly be converted to HTTP. It means that certain protocol specific
 operations might not be available. This is not the case if you can tunnel