diff --git a/Changes b/Changes
index a592022..fc3c150 100644
--- a/Changes
+++ b/Changes
@@ -5,6 +5,7 @@ Revision history for e
 =================
 
 Added commands: max, min (from List::Util).
+Added limit to number of processes with runf (currently set to 20).
 Updated pod.
 
 =================
diff --git a/README.md b/README.md
index 5f9033e..4a55d47 100644
--- a/README.md
+++ b/README.md
@@ -553,6 +553,10 @@ This sector includes commands to run asynchronous
 
 It is not entirely clear which method to always use.
 
+`runf` limits to number of action or 20 (whichever is smaller).
+
+`runt` and `runio` have no such limits.
+
 Typically using threads (with `runt`) seems to be fastest.
 
 Some statistics using different run commands:
@@ -603,6 +607,8 @@ Returns the results.
 
 Takes much overhead to start up!
 
+Will use up to 20 processes.
+
 ### runio
 
 Run tasks in parallel using [Mojo::IOLoop](https://metacpan.org/pod/Mojo%3A%3AIOLoop).
diff --git a/lib/e.pm b/lib/e.pm
index a70ae6d..111a65a 100644
--- a/lib/e.pm
+++ b/lib/e.pm
@@ -587,6 +587,10 @@ This sector includes commands to run asynchronous
 
 It is not entirely clear which method to always use.
 
+C<runf> limits to number of action or 20 (whichever is smaller).
+
+C<runt> and C<runio> have no such limits.
+
 Typically using threads (with C<runt>) seems to be fastest.
 
 Some statistics using different run commands:
@@ -637,6 +641,8 @@ Returns the results.
 
 Takes much overhead to start up!
 
+Will use up to 20 processes.
+
 =head3 runio
 
 Run tasks in parallel using L<Mojo::IOLoop>.
@@ -1128,7 +1134,9 @@ sub import {
                 require Parallel::ForkManager;
             }
 
-            my $pm = Parallel::ForkManager->new( ~~ @_ );
+            my $MAX_PROCESSES = 20;
+            my $processes     = ( @_ > $MAX_PROCESSES ) ? $MAX_PROCESSES : @_;
+            my $pm            = Parallel::ForkManager->new( $processes );
             my @res;
 
             $pm->run_on_finish(