diff --git a/lib/doctest.js b/lib/doctest.js
index a75981bf..a689207f 100644
--- a/lib/doctest.js
+++ b/lib/doctest.js
@@ -202,7 +202,8 @@ function normalizeTest($test) {
 function processLine(
   options,        // :: { prefix :: String
                   //    , openingDelimiter :: Nullable String
-                  //    , closingDelimiter :: Nullable String }
+                  //    , closingDelimiter :: Nullable String
+                  //    , logFunctionNames :: Array String }
   accum,          // :: { state :: State, tests :: Array Test }
   line,           // :: String
   input,          // :: Test -> Undefined
@@ -237,15 +238,17 @@ function processLine(
       (last ($test[OUTPUT])).value += '\n'
                                                                   + value;
       appendToOutput ($test);
-    } else if ((match = /^\[([A-Za-z]+)\]:(.*)$/.exec (trimmedLine)) != null) {
-      accum.state = LOG;
-      value = stripLeading (1, ' ', match[2]);
-      $test = last (accum.tests);
-      $test[OUTPUT].push ({
-        channel: match[1],
-        value: value
-      });
-      output ($test);
+    } else if ((match = /^\[(.+?)\]:(.*)$/.exec (trimmedLine)) != null) {
+      if (options.logFunctionNames.includes (match[1])) {
+        accum.state = LOG;
+        value = stripLeading (1, ' ', match[2]);
+        $test = last (accum.tests);
+        $test[OUTPUT].push ({
+          channel: match[1],
+          value: value
+        });
+        output ($test);
+      }
     } else if (accum.state === INPUT || accum.state === LOG) {
       $test = last (accum.tests);
       if (!$test[OUTPUT].some (isStandardOutput)) {
diff --git a/test/index.js b/test/index.js
index 08516db0..17a948f2 100644
--- a/test/index.js
+++ b/test/index.js
@@ -234,19 +234,19 @@ testCommand ('bin/doctest --log-function stdout --log-function stderr test/share
   stderr: ''
 });
 
-testCommand ('bin/doctest --log-function stdout test/shared/logging.js', {
+testCommand ('bin/doctest --log-function stdout --log-function stderr test/shared/logging.js', {
   status: 1,
   stdout: unlines ([
     'running doctests in test/shared/logging.js...',
-    '.........xx.xxxx..x..x..',
-    'FAIL: expected [stdout]: 2 on line 33 (got 3)',
-    'FAIL: expected 3 on line 34 (got no output)',
-    'FAIL: expected 3 on line 40 (got [stdout]: 2)',
+    '...........xx.xxxx..x..x..',
+    'FAIL: expected [stdout]: 2 on line 42 (got 3)',
+    'FAIL: expected 3 on line 43 (got no output)',
+    'FAIL: expected 3 on line 49 (got [stdout]: 2)',
     'FAIL: expected no output on line - (got 3)',
-    'FAIL: expected [stdout]: 2 on line 45 (got [stdout]: 1)',
-    'FAIL: expected [stdout]: 1 on line 46 (got [stdout]: 2)',
-    'FAIL: expected [stderr]: 2 on line 53 (got [stdout]: 2)',
-    'FAIL: expected [stdout]: 1 on line 60 (got no output fast enough)'
+    'FAIL: expected [stdout]: 2 on line 54 (got [stdout]: 1)',
+    'FAIL: expected [stdout]: 1 on line 55 (got [stdout]: 2)',
+    'FAIL: expected [stderr]: 2 on line 62 (got [stdout]: 2)',
+    'FAIL: expected [stdout]: 1 on line 69 (got no output fast enough)'
   ]),
   stderr: ''
 });
@@ -293,11 +293,8 @@ if (esmSupported) {
     status: 1,
     stdout: unlines ([
       'running doctests in test/esm/async.mjs...',
-      'xxxx',
-      'FAIL: expected [stdout]: 1 on line 4 (got ! ReferenceError: stdout is not defined)',
-      'FAIL: expected [stderr]: 3 on line 5 (got no output fast enough)',
-      'FAIL: expected undefined on line 6 (got no output)',
-      'FAIL: expected [stdout]: 2 on line 7 (got no output fast enough)'
+      'x',
+      'FAIL: expected undefined on line 6 (got ! ReferenceError: stdout is not defined)'
     ]),
     stderr: ''
   });
diff --git a/test/shared/logging.js b/test/shared/logging.js
index 4370c505..d6b29577 100644
--- a/test/shared/logging.js
+++ b/test/shared/logging.js
@@ -26,6 +26,15 @@ function crash(){
 // ! Error
 // [stdout]: 1
 
+// Output on non-existent channels is ignored
+//
+// > (stdout (1), 2)
+// [spam]: "hi"
+// [stdout]: 1
+// [spam]: "lalala"
+// 2
+// [spam]: "whatever"
+
 // Failure due to not enough output
 //
 // > (stdout (1), 3)