My 2 year old keeps vomiting.she is fine in herself. no temp, no diarrhoea & tummy doesn't hurt.could it be a food intolerance or more likely a virus?

Most likely a virus: The most common reason for vomiting in children is related to viral infection. The difference would be that if it is viral , you would not expect it to last but 1-3 days. If vomiting persists beyond that, then consider other causes such as food intolerance , gastric reflux, uti, etc. At that point i would take her to the doctor.

How long?: If this has been present for more than a couple of weeks one will need to consider reflux. If this occurs within 2 hrs after having eaten certain food, then the cause may be mild anaphylaxis to a food allergen but she'd not feel ok otherwise. Vomiting may rarely be the only sign of migraine in young children and the probability higher if the parent also has migraine. Consult a GI doctor.

M.D.: A viral illness is the most likely cause. Other causes include reflux, food intolerance, increased intracranial pressure. If there is a history of family members with the same illness, daycare, associated diarrhea, it is most likely infectious in its cause. Food allergic reactions and food poisoning are other causes. For prolonged vomiting, please see a physician. I hope that this helps.