when was the last time she ate? It is not unusual for them to react to an empty stomach by vomitting yelow/green foamy bile only. A search on this site will show many that feed a couple of cookies or meals later at noght to avoid this, However the 1.30 and 3.OO am time would be early for this occuring unless the dog last meal was 8-12 hours before this time.
also adding that when this occurs there is nothing but bile in the vomit no food etc. secondly it is general small amount in any one spot and the dog general does not have any other symptoms of being sick because it well isn't If this is not the case you can rull out empty stomach syndrome as a cause.
Also keep in mind dogs have a more sensitive gag reflex, they will throwup much more easily when something bothers there guts than humans, this often goes along way in protecting them from when the get into something the should not.
also adding that when this occurs there is nothing but bile in the vomit no food etc. secondly it is general small amount in any one spot and the dog general does not have any other symptoms of being sick because it well isn't If this is not the case you can rull out empty stomach syndrome as a cause.
Also keep in mind dogs have a more sensitive gag reflex, they will throwup much more easily when something bothers there guts than humans, this often goes along way in protecting them from when the get into something the should not.