Development of new drugs/medicines/therapeutic modalities revolutionized the practice of medicine. The new medicine discoveries have converted many once fatal or debilitating diseases into almost routine therapeutic exercises. For example today deaths from cardiovascular disease and stroke have decreased by almost 50% or less over the past 30 years. This reduction is due-in part- to the discovery and increased use of antihypertensive, cholesterol synthesis inhibitors and drugs that prevent or dissolve blood clots. As the number of potential medicines produced increases, the problem of whom to test them on grows. There are two main groups: healthy volunteers and volunteer patients (plus rarely non volunteer patients). Studies in healthy normal volunteers can help to find out the safety, tolerability, pharmacokinetics and for some drugs, e.g. anticoagulants and anaesthetic agents, their dynamic effects. Otherwise for most drugs the dynamic effect and thus the therapeutic potential can only be investigated in patients, e.g. drugs for epilepsy or antimicrobials. Introduction of novel agents into both groups poses ethical and scientific problems.

There are four reasons why medical practitioners (or medical trainees) should have grounding in the knowledge and application of tested principles of experimental therapeutics:
1. Optimal selection of a specific dose of a medicine for a specific patient requires a sound backup of good clinical research. To some extent every new administration to a patient is an exercise in experimental therapeutics.
2. Increasingly doctors are personally involved in patient care.
3. Such studies provide an exercise in ethical and logical thinking.
4. Good clinical research alters clinical practice.

Human Experiments Vs Clinical Research
1. Some people are averse to the word ‘experiment’ in relation to man, thinking man to be a guinea pig. That immediately implies a degree of impropriety in what is done.
2. It is better if all who are concern recognize the true meaning of the word, i.e. to ascertain or establish by trial (Oxford English Dictionary), that the benefits of modern medicine derive almost wholly from scientific experimentation and that some risk is inseparable from much medical advances.
3. The moral obligation of all medical practitioners lies in ensuring that in their desire to help patients (the ethical principle of beneficience)                                                                                                                                                                 4.They should never allow themselves to put the individual who has come to seek their help at any disadvantage (the ethical principles of non-maleficence) as the scientist or physician has no right to choose martyrs for society.

Studies involving human subjects fall into two distinct categories
1.Clinical studies: The class of all scientific approaches to evaluate medical disease preventions, diagnostic techniques and treatments using human subjects (either healthy volunteers or volunteer patients or samples obtained from them) essentially as experimental animals.
2. Clinical Trial: It is a subset of those systematic clinical studies that evaluate the new drug(s) in human subject(s) to generate data for discovery and/or verifying the clinical pharmacological (both pharmacokinetic and pharmacodynamic) and/or adverse effect with the objective of determining efficacy and/or safety of the new compound(s).

These clinical studies are done in four phases of drug development, namely Phases 1, 2, 3 and 4. Phase 4 evaluations of marketed medicines in formal clinical trials using the same or similar types of protocols to those used in Phases 1 and 3 are also referred to as clinical trial. A clinical trial is a method for comparing objectively by a prospective studies the results of two or more therapeutic procedures. Until about 30 years ago treatment methods were chosen on the basis of clinical impressions and personal experiences rather than objective testing. As a result many drugs with undoubted effectiveness remain in use without ever having been subjected to a control trial. As per regulatory requirements any new drug is now needed to have been tested in this way before being licensed for general clinical use. A clinical trial aims to compare the response of a test group of patients receiving a new drug treatment (A) with that of a control group receiving another treatment (B).

The proposed trial should be carried out, only after approval of the Drugs Controller General of India (DCGI), as is necessary under the Schedule Y of Drugs and Cosmetics Act,1940. The investigator should also get the approval of Ethical Committee of the Institution before submitting the proposal to DCGI. All the guiding principles should be followed irrespective of whether the drug has been developed in this country or abroad or whether clinical trials have been carried out outside India or not.