diff --git a/gcm.h b/gcm.h
index ad34d70237cf561416b1b5b83b6994c88afd3840..3f5ae96708de20557adb2d01adb85e7a67e431e4 100644
--- a/gcm.h
+++ b/gcm.h
@@ -97,7 +97,7 @@ gcm_digest(struct gcm_ctx *ctx, void *cipher, nettle_crypt_func *f,
 	   unsigned length, uint8_t *digest);
 
 #if 0
-/* FIXME: IS this macrology useful? */
+/* FIXME: Is this macrology useful? */
 #define GCM_KEY(type) \
 { type cipher; struct gcm_ctx gcm; }