diff --git a/README.org b/README.org
index 77c468a..c1aa437 100644
--- a/README.org
+++ b/README.org
@@ -38,7 +38,7 @@ alt + s
     tdrop -ma -w -4 -y "$PANEL_HEIGHT" -s dropdown termite
 #+END_EXAMPLE
 
-The positional argument
+The positional argument should be the name of a program in =$PATH= (as opposed to the full path to a program) and should not contain any flags (see =-f= if you want to pass additional flags to the program when running it).
 
 ** Basic Flags
 =-s= / =--session= should only be used for supported terminals and if the user wants to start a tmux or tmuxinator session. =-a= / =--auto-detect-wm= should be used to automatically set certain options (=-l=, =-L=, =-d=, and/or =-i=) based on the current window manager. These flags (whether automatically or manually set) may be necessary for tdrop to behave correctly (e.g. they are required for =-w= / =--width=, =-h= / =--height=, =-x= / =--xoff=, and =-y= / =--yoff= to work correctly on tiling window managers). See the manpage for these flags for specific details.
diff --git a/tdrop b/tdrop
index 09e3fc0..0fe2c01 100755
--- a/tdrop
+++ b/tdrop
@@ -161,6 +161,13 @@ done
 shift "$((OPTIND-1))"
 program=$1
 
+# check that the program is not a path and does not contain flags
+if ! type "$program" 2> /dev/null; then
+	echo >&2 "The program should be in PATH and not contain flags." | \
+		tee -a "$MUTDROP_PATH"/log
+	exit 1
+fi
+
 if [[ $# -ne 1 ]]; then
 	echo >&2 "Exactly 1 positional argument is required." \
 		"For help use -h or --help or see the manpage." | \