Hi, Yes, it is safe for the treatment of vomiting. Purpose of taking pregnidoxin is not mentioned, is she pregnant? Pregnidoxin is a combination of meclizine and caffeine commonly used in the treatment of motion sickness and nausea, vomiting, light-headedness associated with vertigo. This medicine may be used to treat nausea and vomiting in pregnant women (morning sickness) as well. However, if she is pregnant I would have preferred her doxylamine with vitamin B-6 twice daily for the treatment nausea and vomiting associated with early pregnancy. It is also safe during pregnancy. The best way to control vomiting is to avoid triggers such as strong odors, excessive fatigue, spicy foods and foods high in sugar. Alternative natural ways to control vomiting like acupressure, acupuncture, and use of ginger. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Mohammed Taher Ali, General & Family Physician