Things you can try at home
The first thing you should do is open their mouth to check if you can see anything lodged at the back of their throat or across the roof of their mouth. Removing a foreign body from the mouth can be painful for your dog and they may bite you, so it is best to let your veterinarian do this.
If there is no obvious obstruction in their mouth, it is time to start thinking about what your dog got up to today. Is there any human food missing off the counter? Or any recently rummaged-through garbage? Did you treat them to a special steak bone or doggy ice cream cone? If your dog got into something they shouldn’t have, or if they overindulged on a food outside of their normal diet, nausea and gastrointestinal upset could be leading to their excessive amounts of drool.
Since there are so many possibilities, the best thing you can do for your dog when they are drooling excessively is to make an appointment with your veterinarian to address the source of the problem.
If the drooling is normal, consider tying a bandanna to your dog so you have easy access to a cloth to wipe their mouths.