It is possible that your pup is getting into and eating something that she shouldn't be. Foaming at the mouth is typical for an animal who has ingested human food items that are not good for them or pesticides or poisonous products. Since this has happend twice, pay close attention to any table food you may have given her as a treat that the two incidents have in common....or try to remember where she was (in the back yard, a certain room, etc.) when the foaming began, so that you can check the area for any pesticides or any things she couldv'e gotten in.
It is always advisable to take your dog to the Vet if something is out of the ordinary as animals cannot tell us what is wrong. It is lways better to be on the safe side. However, if you would like to wait it out a day or two, continue to watch your pups behavior. Also, check to make sure the tongue is pinkish in color and doesn't change a blue or purple color. Also check the CRT (capillary refill time) on the gums by using a finger to push on the gum to see how fast the blood rushes back into the area. The time should be under 3 seconds. Ensure your pup continues to eat, drink and eliminate normally. Keep a good eye out for any even small change in behavior.
Here is a good website on what not to feed you dog incase you are curious....
Let me know if you have any other questions.
Chewing on none food items is a bad habit....I know it is hard to keep them from doing it. I have a 1 yr old pomeranian who chews everything from crayons to baloon to wood and i have to keep a close eye on her.
It is possible that there is something in her air way, however obviously she is able to swallow so it may be something small enough that you cannot feel or see that is caught. Then again, she may have ingested something that you do not know about and is having a minor (if there are no other signs) reaction to that. I think you should get her to the vet and if the foaming has not stopped by now. Your DVM may need to do blood work and if that is normal, meaning she probably didn't ingest any liquids that are upsetting her blood levels, then he may decide to do x-rays of the throat to ensure there is nothing stuck there.
Just incase your interested....
The last time I seen this was when a yorkie came into our clinic. The owner had brought her in as soon as she began having exessive drool and foam coming from the mouth. We did all kinds of bllod work on her thinking that she may have gotten a hold of some pesticides. There were a few small lows and highs in the bloodwork but nothing to begin any treatment as we still did not know what was wrong. As the dog was acting normally and drinking, eating and eliminating normally, he figured that maybe sometime after the bug truck went by spraying, the dog later went out in the back yard and had some type of small reaction. He never really figured out exactly what happend but he sat with the pup for the rest of the afternoon and then sent her home. Thankfully the yorkie was fine and was back to normal the next day. This is just a story for you to compare yours too. Do not let this under estimate what can happen and take the place of seeing the DVM.