Drontal plus xl worming tablets you can worm a 35 kg dog with just one tablet while there is no tablet or injection you can give a dog which will prevent a worm infection but you can still protect him with drontal worming tablets the best you can do is to kill any worms which may be present on a regular basis to avoid worms reaching maturity and affecting your pets health you should worm your pet regularly worming every three months will also reduce other health risks ask your vet wh