Physicians or doctors promote, maintain or restore human health through the study, diagnosis and treatment of disease, injury or other physical and mental impairment.

Specialists may focus on certain categories of disease, certain patient groups or certain methods of treatment, while general practitioners are responsible for providing continuous and comprehensive medical care to individuals in the community. There are a wide variety of qualifications for doctors and physicians throughout the world, although their training involves common elements. Medical ethics, for example, require that physicians treat their patients with consideration and compassion.

Among the most common challenges faced by health professionals are the unwillingness of citizens to look after their own health; lack of effective public education on health issues; negative impressions (whether false or otherwise) of the role of money in the medical profession; controversies surrounding reproductive rights and other demographic issues; and under-staffed and/or under-equipped facilities.

Physicians play a vital role in minimising risks to human health and in raising awareness of the links between health and the environment, which in turn can promote environmentally responsible behaviour.

Occupational physicians are specialists who provide services related to the health of workers and employers. They focus on the inter-relationships between workers, workplaces and work practices. Their work includes prevention, treatment and rehabilitation. Occupational physicians consider medical issues within the wider context of the psycho-social, industrial and motivational framework of the workplace.

In recent decades, the international community has begun to pay greater attention to the environment as a major determinant of health. Environmental factors are estimated to account for almost 20 percent of all deaths in Europe. In 1989, in response to growing evidence of the impacts of the environment on human health, the World Health Organization (WHO) took the first steps towards creating a broad public health approach based on primary prevention and inter-sectoral policy making. Since the launch of the health and environment process, the emphasis has been on: 
  • the impacts of climate change on human health and the environment;
  • the risks to the health of children and other vulnerable groups of exposure to poor environmental, working and living conditions (especially lack of clean water and sanitation);
  • socioeconomic and gender inequalities in health care and living conditions, exacerbated by the financial crisis;
  • non-communicable diseases, and in particular the extent to which they can be reduced by adequate policies in areas such as urban development, transport, agriculture, food safety and nutrition, and living and working environments;
  • persistent, endocrine-disrupting and bio-accumulating hazardous chemicals and (nano)particles; and
  • obesity, physical activity and healthy diets.

Further information can be found in the Parma Declaration on Environment and Health, issued by WHO Europe at the Fifth Ministerial Conference on Environment and Health, held in March 2010:
New information is constantly emerging about the presence of carcinogenic substances in the environment. Physicians have an important role in advising their patients on how to reduce health risks by making changes to their lifestyles and behaviour:
  • Choose fruits and vegetables rather than fatty foods. Wash fruits and vegetables carefully in clean, running water to remove pesticides and germs.
  • Stop smoking. If you are surrounded by heavy smokers, ask them to smoke outside. If you live with a smoker who does not want to be kicked out of the house, designate a well-ventilated smoking room. Warn other residents not to spend time in the smoking room.  Ask your guests to smoke only outside or in the smoking room.
  • If you need to use pesticides, insecticides or other chemicals in your home or garden, first read the instructions carefully.
  • Read the labels on paint pots to make sure they do not contain hazardous substances. Do not use any materials that are recognised as (probable) carcinogens (e.g. benzene, carbon tetrachloride, trichlorethylene and dioxin).
  • Wear rubber gloves and a mask when using a lawnmower or other machine that runs on petrol. Petrol contains benzene, which causes leukemia. Do not breathe petrol fumes and avoid contact with the skin. Petrol penetrates the skin easily, especially through scratches or abrasions.
  • Leave work with asbestos to a professional. Asbestos was once commonly used as a coating and can still be found in many old buildings. If the coating is undamaged, the asbestos poses no significant risk. However, once the coating has been broken, asbestos fibres can be inhaled and enter the lungs, causing cancer.
  • Exercise regularly and keep an eye on your weight.