Zentel (albendazole) is generally safe and effective for treating parasitic worm infections in children her age. However, stomach pain, nausea, and loss of appetite can stem from various other causes, like a mild viral infection or indigestion, rather than worms. Giving her Zentel without a clear diagnosis might not resolve her discomfort. It is safest to have a pediatrician evaluate her first to identify the exact cause of her symptoms. In the meantime, try to keep her hydrated with small, frequent sips of water and offer simple, bland foods when she feels ready to eat.