diff --git a/fasd b/fasd
index b1e64f4..1cdd049 100755
--- a/fasd
+++ b/fasd
@@ -115,7 +115,7 @@ EOS
       zsh-hook) cat <<EOS
 # add zsh hook
 _fasd_preexec() {
-  { eval "fasd --proc \$(fasd --sanitize \$1)"; } >> "$_FASD_SINK" 2>&1
+  { eval "fasd --proc \$(fasd --sanitize \"\$1\")"; } >> "$_FASD_SINK" 2>&1
 }
 autoload -Uz add-zsh-hook
 add-zsh-hook preexec _fasd_preexec