How to Prevent Drawers From Falling Out

Sliding drawers give easy access to the items inside, but you can yank them right out of the dresser or cabinet if it doesn't include a stopping device. Pulling drawers out of a dresser can be both an inconvenience and a hazard. In the best case, the drawer can fall and spill clothes all over the ground. In the worst case, the heavy wood can crash down on an unprotected toe and shatter bones. Installing a simple wooden stop can help prevent drawers from falling out, saving both your folded clothes -- and your toes.

Older drawers with wooden runners may not have stopping mechanisms.

Drill a hole 3/4 inch from one end of the wooden block. Make the hole the same diameter as the screw you'll be using later.
Screw the block into the drawer's rear panel, with the block located inside the body of the drawer. Position the pre-drilled guide hole at the bottom of the block, and use a screw long enough to hold the block in place but short enough that it doesn't stick too far out of the rear of the drawer panel. Allow the upper half inch of the block to rise over the lip of the drawer panel. Tighten the screw just enough that the block is held securely in place, yet can still be rotated around the screw by hand.
Rotate the block on its screw until it sits horizontally. No part of the horizontal block should protrude over the top of the drawer's panel.

Slide the drawer partially into the dresser or cabinet. Push it in just far enough that the drawer catches on its runner or slide, but you still have easy access to the block you screwed to the rear panel.
Rotate the block back to the vertical position, and finish sliding the drawer into its slot. The block will catch on the cabinet's frame and prevent the drawer from pulling out.
Repeat the process for each unsecured drawer.