Before mass production of medications compounding was a routine skill for many pharmacists and physicians. Compounding pharmacists who have experience with compounding techniques are now less common. Compounding enables Crosby's to create particular pharmaceutical products to fit the unique needs of each patient. This may be done for medically reasons, such as changing the form of the medication from a solid pill to a liquid, avoid a non essential ingredient that the patient is allergic to, or to obtain the exact dose needed. It may also be done for voluntary reasons, such as adding flavors to a medication. Crosby's also has and maintains a "state of the art" clean room, with both positive and negative air flows. This allows us to compound medication in a sterile environment for the patient. These sterile rooms are inspected and certified on a regular basis by an independent lab for quality control purposes.