diff --git a/ChangeLog b/ChangeLog
index 797c0fe76b..238af8a35b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Fri Feb 11 23:27:50 2011  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
+
+	* ruby.c (proc_options): add --gem=enabled as an alias of
+	  --enable=gems and --gem=disabled as an alias of --disable=gems.
+	  Gem named "enabled" or "disabled" has already been reserved
+	  legitimately for this purpose.
+
 Fri Feb 11 23:17:04 2011  Tanaka Akira  <akr@fsij.org>
 
 	* ext/dl/cfunc.c: parenthesize macro arguments.
diff --git a/ruby.c b/ruby.c
index 86d779e63b..87ca6bed23 100644
--- a/ruby.c
+++ b/ruby.c
@@ -1072,7 +1072,15 @@ proc_options(long argc, char **argv, struct cmdline_options *opt, int envopt)
 		add_modules(&opt->req_list, s);
 	    }
 	    else if (is_option_with_arg("gem", Qfalse, Qtrue)) {
-		add_gems(&opt->req_list, s);
+                if (strcmp("disabled", s) == 0) {
+                    opt->disable |= DISABLE_BIT(gems);
+                }
+                else if (strcmp("enabled", s) == 0) {
+                    opt->disable &= ~DISABLE_BIT(gems);
+                }
+                else {
+                    add_gems(&opt->req_list, s);
+                }
 	    }
 	    else if (strcmp("version", s) == 0) {
 		if (envopt) goto noenvopt_long;