The purpose of clinical testing on pharmaceutical drugs is to see how well the drug accomplishes its intended purpose as well as identify any and all side effects that the drug can cause so that they can be listed for the patients that do take the medication. Without this testing, there is no way to see if the drug that is being produced is even safe for humans to take, let alone effective. If a drug were to ever be used as a medication without any testing done on it beforehand and it has an adverse effect on a patient, no one would know what to do because no one actually knows anything about the drug itself. With the clinical testing, companies are able to see how effective the drug is at doing its job, what side effects can occur, how it interacts with other drugs, etc. All of this knowledge is essential to know so that the patients who use this drug are taking it as safely as possible, and it can only be obtained through clinical testing.