what to do if child drinks rose water by mistake   

Rosewater does not have any harmful effects so do not worry if your child ends up drinking rose water by mistake. Rosewater is basically used for topical application though it is also used in many sweet dishes and desserts. But when we buy such products from the market, we never know how natural they are so try to keep such things out of reach of children to avoid any complications. If you are worried too much, better to consult your paediatrician to be on the safer side.