This guidance provides recommendations regarding the use of restricted delivery systems , to limit unintentional ingestion of oral liquid drug products (e.g., oral solution, oral suspension) by children. The recommendations in this guidance apply broadly to oral liquid drug and biological products. , Accordingly, this guidance is intended for manufacturers of oral liquid drug and biological products. In this guidance, the term manufacturer is used broadly to include firms that market drug products under the Over-the-counter (OTC) Drug Review; holders of new drug applications (NDAs), biologics license applications (BLAs), and abbreviated new drug applications (ANDAs); and firms that manufacture components packaged or labeled for commercial distribution with oral liquid drug products, including firms that buy product in bulk to sell under their own label and add a flow restrictor to the product when they fill the bulk product into direct-to-consumer packaging.