1976
Working in the High School Department of Human Genetics & Biology, noted that laboratory animals displayed greater resistance to oxidative and other stressors when previously supplied with antioxidant vitamins.

Studied Dr Hayflick's research work regarding the influence of tocopherols on in vitro human cells, which caused an increase in life span which did not correspond to so-called biological clock limits.

Self experimenting using various antioxidants and micronutrients.

Began collecting all available technological data relating to antioxidants for human consumption. His father, (Director of technology for a company specializing in enriching and preserving food products using vitamins and antioxidants and a winner of several European Awards for innovations in technology), provided the young Petrovic with access to international industrial information on antioxidants emanating from Japan, USA and Europe)

1981
Enrolled at Medical University of Belgrade

1982
Appointed principal student demonstrator/assistant at the Department of Histology & Biology (Human Genetics). Enjoyed full access to university research material related to the specific role played by antioxidants in biological systems.

1983
In addition to lecturing at the Medical University/ Department of Clinical Nutrition, started to explore the possible role of vitamins and antioxidants in the prevention of heart disease.

1983-89
Continued research in this field within various Departments on behalf of the Department of Internal Medicine. Findings of this study inferred that antioxidants produce optimal effects when taken together according to synergistic principles, and indicated that certain antioxidants could possibly reverse heart disease through prevention of cholesterol oxidation and activation of LCAT enzyme.

1989
Presented his concept of arteriosclerotic regression to a group of academic medical professors and WHO (World Health Organization) experts during the official State Examination for Medical Experts.

Graduated as Medical Doctor with Honors Degree from the Medical University of Belgrade.

Received congratulations for his concept and was officially classified as "best in class",with an average note of 90.3%. After sitting the official State examination, was awarded an unprecedented honour mark of 10+

1991
Continued researching antioxidants and vitamins while working in a private practice which included hundreds of heart patients.
Carried out an independent study on the effects of antioxidants and related components on heat disease symptoms such as high blood pressure and angina pectoris. Presented these results to Prof Dr Med Simic, World Health Organization expert on nutrition, as well as to individual medical professors.

1992
Continued independent research in Greece, Germany and a few other European countries collecting all available data pertaining to antioxidants
Arrived in South Africa in 1992 to continue research into heart disease(RSA has one of the highest incidences of heart disease in the world)

1993-4
Continued research in antioxidant micronutrients and synergistic combinations of antioxidants. Presented his theories to Professor W J Serfontein, ,Professor Emeritus, Department of Chemical Pathology, University of Pretoria who responded (April 1993):
"I think that Dr Petrovic's proposal should receive serious attention."

1994
Administered a program of non-prescriptive, non-scheduled antioxidants and micronutrients to a previously diagnosed CFIDS sufferer of 10 years who reported a remission of symptoms within four days.
Continued working with CFIDS patients, obtaining highly encouraging results.

1995
Started with activities on the international scene and started treating patients outside RSA.

1995/6
Received congratulations for his work by all three associates of the double Nobel Prize Winner Dr Linus Pauling, Dr Mathias Rath (USA),Dr Brian Leibovitz (USA), Dr Richard Passwater (USA)

In 1996 His work becomes independently scrutinized by Dr Kilroe Smith, a medical biochemist and a former director of the RSA Institute for Occupational Health, who published more than 80 papers in prestigious international medical journals. In 1998 Dr Kilroe-Smith describes Dr Petrovic's CFIDS Protocol as a "cure for CFIDS"./1998 RSA Study/International Study Report/

1996-99
Continued research in the CFIDS field and coordinating international activities of his info CFIDS centers /patients' associations in the UK ,USA and Australia

2000-2014
Conducting intensive research in both CFIDS and secondary superimposed autoimmune entities and/or entities with autoimmune component that very frequently develop in CFIDS patients and that typically include:

-Chron's disease
-Lupus Erythematosus
-Ulcerative Colitis
-Rheumatoid Arthritis
-Asthma

In initial pilot studies all patients suffering from CFIDS and Chron's disease reported full recovery on the CFIDS Protocol. Full clinical reversal of Chron's disease has been confirmed via both clinical and histological examination ( biopsy) by independent medical centers in both Australia and RSA.

All randomly selected patients suffering from CFIDS and other superimposed entities referred to above, also reported full recovery.

His work in immunomodulatory properties of antioxidants and accessory micronutrients has become basis of novel clinical approach relative to optimal therapeutical management of CFIDS that is followed by top USA CFIDS specialists as well as inspiration for Prof Dr Martin Pall's international bestseller "Explaining Inexplainable Illnesses"published by Washington Medical University.