Aralen may be prescribed by your doctor to prevent or treat malaria, a disease that is caused by parasites. Malaria is common in areas of the world such as Africa, South America, and Southern Asia. Aralen is a prescription strength medication that is taken orally as directed by your doctor and is available as Aralen or the generic alternative Chloroquine Phosphate. Aralen should be taken with food to help prevent stomach upset. The generic alternative is not manufactured by the company that makes the brand product.