diff --git a/man7/capabilities.7 b/man7/capabilities.7
index ba90be15c..785a5611d 100644
--- a/man7/capabilities.7
+++ b/man7/capabilities.7
@@ -1514,6 +1514,8 @@ operations.
 The
 .B CAP_SETPCAP
 capability is required to modify the flags.
+Note that the named constants are only available after including the
+<linux/securebits.h> header.
 .PP
 The
 .I securebits