The process of developing drugs and bringing them to market is long, complex, and expensive. Basic biochemical research, which may take place in universities or in government or industry laboratories, can suggest directions for drug development. Most actual drug development takes place in industry laboratories, paid for by the extremely large and wealthy pharmaceutical industry. Once a drug is developed, it must be tested for efficacy, safety, and tolerability. Efficacy reflects how well it treats the target symptoms. Safety relates to the absence of dangerous side effects, otherwise known as adverse events. Tolerability reflects a patient’s ability to tolerate the drug. A drug may be safe—that is not dangerous—but still intolerable. For example, it may cause nausea or headaches.