Probiotics are found in any dog boutique. I do not know if the main pet stores are carrying them, but perhaps! You can learn more about them online. It is a powder added to their food. Makes a great difference. My male has upset stomach like that and will eat a little, then comes back a half hour or so later and finish the meal. The vet explain that if they have been off food (overnight) and did not eat enough before that "fast", their stomachs can get some acid reflux type of situation and they will either throw up, or feel ill. I will generally give Jasper something to eat before he goes to bed, if he has not eaten since early evening. That helps him the next day. It is usually only a small treat (i.e., carrot, dehydrated lamb or beef, etc.). I have found them to have somewhat sensitive stomachs; particularly when their is any change. My female has an iron stomach, but the male is delicate and any change in schedule or more people around than usual, or arguments, gets a change in his bowel movements. It could also be a little flu bug going through them. Regardless, i have found ground flax added to the food helps with avoiding diarhea and binding them a little and the probiotics are used particularly when antibiotics are in their system or they are having distress stomachs. Good luck!