How do you fix drawers that fall out of the dresser when you open it?

Is it possible that the center piece that the draw groove on bottom is too small? That's my problem I have no idea how or why but it was a hand me down from a friend and I just haven't bothered with it. Check and see that can be fixed simply by taking measurement and having it cut by store for a small price then just remove the one there mark screw or nail marks and replace with proper piece of wood.

Fix some stops.

Take the drawer out and see what is broken. Some drawers have a plastic piece underneath (center front) that fits over a piece of wood running from the front to the back in the center of the opening. Other drawers have pieces of wood (slides) on either side of the opening that the drawer rests on. You need to figure out what the specific problem is and go from there.

For each drawer cut 2 two inch pieces of wood. Screw the pieces to the top of the inside back of the drawer with just enough sitting above the to prevent the drawer from clearing the opening. While the drawer is out turn the attached pieces sideways then install the drawer. With the drawer back clear of the face reach in and turn them up and hand tighten the screws.

I picked up a "free dresser" with the bottom drawer that fell out. However there were two other drawers that worked and gave a perfect example of what to do to fix it. Pull out all drawers and see if you can find at least one example. If that doesn't work for you try something like this. https://www.lowes.com/pd/Richelieu-2-Pack-16-in-Drawer-Slide/50041726

Put a nob at the end of the drawers that will bounce on an end of the frame

We've had several older dressers with this problem. You need to remove the drawer and see how it was put together. The type we've had, had a piece of wood in the center of the opening under the drawer. The wood had two channels cut into it that ran parallel on each side down the length. Under the drawer there was a piece of metal or plastic the slipped into the grooves. As time had passed the channel got wider or broke off. That thin strip of wood was designed to bear the weight of the whole drawer when it was pulled out. It can be replaced by new gliders (measure how much space there will be) more modern types. Or another piece of wood to replace the broken one and be sure to add some stops to prevent this

"new" drawer from being pulled out too far.

Oh, I hate it when that happens. We had a cheap dresser that did the same thing no matter what we tried. My hubby came up with a brilliant plan that was easy to do. You can find the tutorial here - https://acraftymix.com/blog/fix-broken-drawers-quick/

The drawer guide has been broken or removed. You'll need to replace the guide or runners as others have suggested.

Hi Peg: One thing I have done is to put a screw about an inch and a half or two inches in the centre of the top of the area where the drawer comes out, by the front. Have it sticking down about 1/2 inch below the back of the drawers back panel. This will stop the drawer from coming out all the way.