Eisai develops, manufactures, and distributes prescription pharmaceuticals, primarily in North America and Japan. Prescription drug sales account for a majority of the company's revenues and are led by Aricept, which treats Alzheimer's disease. Other drugs include Pariet (known as AcipHex in the US), an acid reflux and ulcer treatment. Development programs target neurology, oncology, vascular, and immunological ailments. In addition, in Japan Eisai distributes over-the-counter drugs and consumer health products. The company also makes chemical active pharmaceutical ingredients (APIs).