Vomiting may be caused by many different factors (intoxication, ingestion of foreign bodies, dyspepsia, gastritis, ulcers, gastric torsion, metabolic problems, etc.) but all the cases need veterinary treatment. If vomiting is repetitive, the case is even worse.
The first step in every case is NOT letting the animal drink any water, since much liquid ingestion usually causes more vomiting, and thus the situation becomes a vicious circle (vomiting-liquid ingestion-vomiting).