Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
How long has they been showing signs?
What does the diarrhea and vomit look like?
Can both dogs keep any water down?
Are their gums nice and pink (not white/pale)? Moist or sticky?
If you press on each one's belly, any tensing, tenderness, discomfort, or pain?
Could they have eaten anything they should not have (ie bones, toys, plants, chemicals, human meds, etc)?