My chihuahua is 1 1/2 years old and since I got her at 8 weeks of age, several times a month she throws up yellow bile. It always happens at around late morning usually at between 11-12 pm. The vet doesn't seem to be too concerned but I'm getting tried of cleaning up. This happens around 3 times a month. Does anyone know what could be causing this and how to prevent it? I heard things like chewing on rawhide, going too long without food and haivng too much variety in food, but none of this seems to make any difference. Any advice would be appreciated. Thanks.