BMC Public Health 2004, 4 http://www.biomedcentral.com/1471-2458/4/11 research methods, have consistently shown that SC is the most dominant form of primary care in both developed countries with better health infrastructure and higher lit- eracy rates as well as in developing countries, where the majority of the people are poor and do not have access to professional health care. In the health diary method to study health care behaviour, participants record perceived illness symptoms and how they respond to them over a period of time. Several health diary studies reveal that only a small proportion of illness is cared by professionals, much of the illness is cared by the individual and the family [13,14]. Mothers take the most active part in caring for ill children within the family [15]. Use of over-the-counter medicine is the most fre- quently reported illness management activity in some studies [16-19]. Population based cross sectional studies reveal similar findings. At any point of time, majority has physical symptoms and only a small proportion seeks profession medical care for help. Most of these symptoms are man- aged by SC or care from family members or friends [20]. Studies conducted at national level in different countries also reveal similar distribution between SC and profes- sional care. For example, a study in early sixties showed that in England and Wales, a vast proportion of morbidity related to both common illness and chronic illness was not treated by medical practitioners. Indeed, the treat- ment provided by medical practitioners was only the "tip of iceberg" [21]. Similar findings were reported from an international study on health care utilization in three dif- ferent countries- US, UK and Yugoslavia [22]. A recent study in Mexico shows that SC represents the most common response to illness. Important determi- nants of SC are socioeconomic conditions (common among poor) and place of residence (common in the rural areas) [23]. It is estimated that 65 to 85% of all health care is provided by the individual or the family, without professional intervention, using folk, non-allopathic or allopathic technology. SC appears to encompass activities related to HP, disease prevention, illness and injury treatment, chronic disease management and rehabilitation. The fam- ily functions as a basic health care unit with an elaborate system of beliefs and procedures, many of which are rooted in the local culture. All levels of professional pri- mary care are thus only supportive to SC and modest facil- itation of it has the potential to improve the health and socioeconomic status of the whole population [10,24]. Categorization of SC Some researchers have classified SC into health SC, which includes activities aimed at maintaining and improving health and medical SC, which includes activities under- taken in response to medical problems [25]. Others have proposed four different types of SC: i) Regulatory SC, which includes routine health maintenance activities such as eating, sleeping and personal hygiene, ii) Preventive SC, which refers to practices like exercising, dieting, self- examination, iii) Reactive SC, which refers to self-initiated responses to symptoms that have not yet been labelled by physician as illness, and iv) restorative SC, which is com- pliance to a professionally prescribed medication regimen [26]. Rapid growth of SC activities in North America and Western Europe From 1970s onwards, there has been a massive growth of SC activities in North America and Western Europe. An explosion of health texts on SC has occurred. Information technology has revolutionized the availabil- ity of information on health to the consumers. The area of consumer health informatics, which deals with issues related to information on health and medical care to con- sumers through the application of information technol- ogy, has expanded rapidly [27]. In the US, exciting development in this area include designing a new genera- tion of software programmes for home management of many chronic diseases like AIDS, substance abuse, diabe- tes, depression, formation of electronic self-help groups. In effect, the industrial age medicine is being replaced by information age health care in the US. In industrial age medicine, developed nearly a century ago, health care was primarily provided by professionals at primary, secondary and tertiary levels overlooking SC, which is the most per- vasive form of health care. In information age health care, lay persons manage a vast proportion of illness by them- selves using information from various sources and as a result, the role of professionals in health care diminishes. The information age health care is contrasted with indus- trial age medicine in Figure 1[28]. The numbers of self-help groups, which are voluntary groups formed by individuals affected by a particular dis- ease or chronic condition for mutual caring, burgeoned. Early examples of such groups include Alcoholic Anony- mous in the US and subsequently these were formed for many chronic illnesses including psychiatric disorders, diabetes, hypertension, different types of cancer and dementia [29]. In Germany, the number of such groups has grown to about 60000 by the year 1995 [30]. SC clearinghouse supports the formation and continua- tion of self help groups, links community and profession- als to these groups and provides information, education Page 3 of 12 (page number not for citation purposes)