diff --git a/share/man/man9/mbuf.9 b/share/man/man9/mbuf.9
index 4cf163f53d84..b10e6ea73a7c 100644
--- a/share/man/man9/mbuf.9
+++ b/share/man/man9/mbuf.9
@@ -278,14 +278,14 @@ on failure.
 The
 .Fa how
 argument is to be set to
-.Dv 0
+.Dv M_TRYWAIT
 or
-.Dv M_NOWAIT .
+.Dv M_DONTWAIT .
 It specifies whether the caller is willing to block if necessary.
 If
 .Fa how
 is set to
-.Dv 0 ,
+.Dv M_TRYWAIT ,
 a failed allocation will result in the caller being put
 to sleep for a designated
 kern.ipc.mbuf_wait
@@ -295,6 +295,14 @@ number of ticks.
 A number of other mbuf-related
 functions and macros have the same argument because they may
 at some point need to allocate new mbufs.
+.Pp
+Programmers should be careful not to confuse the mbuf allocation flag
+.Dv M_DONTWAIT
+with the
+.Xr malloc 9
+allocation flag,
+.Dv M_NOWAIT .
+They are not the same.
 .It Fn MGETHDR mbuf how type
 Allocate an mbuf and initialize it to contain a packet header
 and internal data.