diff --git a/hwg_gssr_scripts/find_dup_begins.pl b/hwg_gssr_scripts/find_dup_begins.pl
index 48c0994..003ea65 100755
--- a/hwg_gssr_scripts/find_dup_begins.pl
+++ b/hwg_gssr_scripts/find_dup_begins.pl
@@ -217,6 +217,9 @@ sub _printUsage {
 -r|--reverse
 Required.  The file of the reverse direction sequences to be searched.  
  
+WARNING: This script puts the entire forward fastq file into memory, so
+use with extreme caution on large files.
+
     );
     print "\n";
     return;